We are living in a 40+ year old house built with cinder block on the outside walls.
When asking builders about doing so on our next house, they all say that no one uses cinder blocks anymore, dismissing the idea.
Why is no one considering that material, with the price of regular framing getting so high as to be practically the same for both, except for the larger footing necessary due to the extra weight of the blocks?
It definitively would be termite proof. They have metal strips that can be nailed to the blocks to hang sheetrock from and the wiring/pipe can be run in there, before blowing insulation in the block walls.
We just built a well house out of that and it seems fine building material. With a brick finish, as in regular framing, the airspace there would insulate the blocks from thermal bridging.
What are we missing? Why is it “not done anymore for houses”?
Replies
Pick up any 'Dwell' at the newstand and you'll typically find more than one house built out of concrete block. AFAIK, there's still plenty of commercial buildings built that way, too. Maybe talk to a commercial builder?
I built mine out of block. The reason why, carpenter cannot do it and they not much left for a carpenter to do. Just plan on filling all the cells with concrete, its not that much more the extra concrete help on heating and cooling.
the main reason why is that crete has an R-Value of only about R-1 per foot compared to wood at about R-1.5 per inch and various inexpensiver insulations at R-3.5 per inch and foams at R-7 per inch.
An eight inch block/crete wall has just under R-1 total but an SIP wall is more like 25 times as good.
With higher energy costs and standards, it can be hard to insulate an exterior wall built with block. Furring and faom are needed to bring it up to standards..
Excellence is its own reward!
I believe it's somewhat regional. My understanding is that it's a lot more common in the south. It is definately still done.
If you decide to go that way, I'd recommend that you pour the cores with concrete and insulate with foamular or similar ON THE OUTSIDE. All that thermal mass inside the insulation "envelope" will mitigate indoor temperature swings in a big way. You can brick over the foam or stucco it. For a really top notch job, put 2" foam up with washers and tapcons, then use wooden pins or sharpened pop-sicle sticks to fasten on another 2" of the same foam. The wooden fasteners don't damage the actual finish r value like metal fasteners do. 4" of foamular has an r value of 20, I believe.
Whether you will be using AC, swamp cooler or heat pump to cool with, you can run the thing full blast at night and then shut it down during the day. With lots of mass inside the insulation you can usually get by without running the cooling system during the day when the system then has to work the hardest (and costs the most to run!).
Are you planning on concrete floors or ?? If you have concrete floors that will, of course, add even more thermal mass. The walls, however, help more with the cooling in summer than the floor.
Any jackass can kick down a barn, but it takes a carpenter to build one.
Good ideas, but the foam on outside makes for a termite home unless it is treated with borates.
I think the reason vermiculite lost followers was that it often contains modest amounts of asbestos as a result of the mining.
You've got your puff wheat.
You've got your puffed rice.
Vermiculite is your puffed mica. Some of the best mica comes from the same places aas asbestos.
Excellence is its own reward!
Wow! Thank you for all these very good answers and ideas.
Vermiculite is what we used on the inside of the blocks in the well house. Poured it in there right out of sacks. I was thinking on the insulation for houses sprayed in there until it comes over the top. This way it would seal all openings well.
Yes, I was thinking that an air barrier between the block and brick exterior would be then enough for R 20 or so and not have the foam that insects/rodents may like to nest in. For stucco, we would have to go with EIFS and that is too touchy to do right. Regular stucco right on the block, as we have here, would not be very efficient to heat and cool.
A few connections shouldn't change that insulation ratio much, any more than it does in wood, compared with the mass.
I talked to one mason and he said the cost is about like regular stick framing is today, high as it is right now, except for the extra footings and that is not that much more. He would like to subcontract the job to a builder. He is really good, as is his son that helps him. He is building on a school now. He is also a house inspector. ;-)
On a gabled house, do you go up the gable end or stop at the ceiling height? How about the attached garage, do you use block to that house wall and then use block or regular framing on the garage? Maybe better to detach the garage and have a breezeway?
Bids will be in next week on the bloated-up plan the architect made, that went from our 1900 to 2360 square feet. Have cut down plans already on hand, expecting bids way too high. No sense on overbuilding for this farm site.
That is why it will be a chance to rethink again how to proceed and this conversation is extremely helpful. Thank you.:-)
What's a health pump?
;)
From my memory of southern styles, the masonry walls stop at top of wall and gable ends are siding on gable trusses or the roof is a hip.
I didn't know before that you are planniing brick exterior but that makes sense in texas. I was picturing one of the block places in Florida loke Brownbag has for himself.
The idea of ICFs is a good one. Much more stormproof for your area..
Excellence is its own reward!
We don't have to worry with humidity or large rainfall events but our temperature extremes have been about -10F to 110F, seems like on the same day sometimes.;-) We have real heating and cooling needs.
I guess that we would still need a tornado "safe room", even with concrete block walls? If so, maybe then make it out of a corner, since we already will have two walls for it, rather than an interior closet?
If built with regular CMUs you would need filled cores with rebar re-inforcing. A block wall will blow over pretty easily.
Since you are ready to start the slab, it is best if you know what the end goal is since rebar should be attached into the slab..
Excellence is its own reward!
The mason I talked to explained about the right kind of block for this job and that there would be rebar in the concrete pad sticking out to put the blocks over and cement them to it for the walls, as there was for the well house.
The trouble with any underground basement or storm shelter is that it is hard to get into for older people, especially when in a wheelchair. In her later years, Grandma (who passed away at 99) would refuse to be taken to the basement when she could not go there herself anymore, said she was taking her chances on top, so we all did. Luckily, the few tornadoes that came close didn't hit this house. Two came within some 100 yards from where the old house was and the new house will be.
Tornadoes are serious stuff around here.
I had all the paperwork from Texas Tech for tornado shelters but someone kept it. Was going to order more but the builders here all said that they build them all the time to those specifications, so I didn't.
We have a proper foundation plan with all the specifics on the kind of concrete, thickness in different places and such for the house they are bidding on now and will have for the changed one if it gets to that, as I expect may need to happen.
The new cut down plan went down from our original 42' by 50' that the architect made into 46' by 54' plans, disregarding that we had told him those were outside measurements, to 36' by 50'.
We are keeping the east features we have now in this house that flow so well and cutting down the west three bedrooms to two, rearranging that part of the house. If the architect now uses the measurements as he did before, it will still come around 1800 square feet, not the 2358 he made the other one.:-(
It is really a matter of principle. No need to be greedy and overbuild for the needs, location and intended use. If someone later wants more, they can remodel and add to their heart's content.
There is a balance to all things in life and ours doesn't measure in a big house. Feel lucky just being able to build one, things being like they are for so many others...
We do want a fine house of nice details, not the biggest house money can buy us.
I have learned much of this right here.:-)
The help I had on laying my CMU was $1 a block plus materials. A normal prices is about $1.50. Do not pay over that. As far as R factor, yes that is right but my goal was thermal mass, termite proof, hurricane resistance and no maintained. I filled my CMU full of concrete and rebar from slab to peak of gable, a 4000 pea gravel pump mix, It really wasn,t that much considering, code you must fill corners, doors every four feet ant lintel bond beam. Couple extra yards fill everything.
But with thermal mass the walls take about 12 hrs to heat up and about 12 hrs to cool off. So it stays a constant 71 degrees most of time, summer it got to 78. But it does not get cold here. If I was up north thermal mass would not work unless I got a lot of sun. Everybody talks about R factor, that is the resistance of heat to move through a material. I,m using the sun to heat and cool by thermal mass so I have not much R factor but I do have a high wind and moisture resistance, which feels like cold. On a cold windy day you feel the cold. I want the heat to move, It release the heat build up at night and it release the cool build up in the day so it stays constant.
On Insulation I have R on studded walls and R 85 in attic. Its total electric with a wood stove just in case. My highest electric bill so far as been $36 . It has electric strip heat with four ton heat pump. Big front porch to high afternoon sun and no windows on north side or south.
The only problem with cmu is mold by moisture traveling through block so some type of waterproofing is mandatory. I used a waterproofer behind walls and a stucco type paint on outside.
---"The only problem with cmu is mold by moisture traveling through block so some type of waterproofing is mandatory. I used a waterproofer behind walls and a stucco type paint on outside."---
Moisture? What is that? We will have household moisture inside but outside we average about 13 all year. Condensation will be minimal from that side, I think.
We were thinking about an airspace and brick veneer with drain holes at the bottom for that, but would have to leave that to the builder, to know what would be best here.
The mason I talked to built his house and several others with block and I think he knows what problems we may have, but I will run this by him, if it comes to being able to build with block. Thanks!
"Moisture? What is that? ...we average about 13 all year."
LOL
and three inches of that is in the form of hail that bounces off the walls!
;)
Brown has solid points about the thermal mass that will help you for three seasons. winter will still need some heating though, as I'm sure you know..
Excellence is its own reward!
---"...and three inches of that is in the form of hail that bounces off the walls! ;) "---
Oops! I meant to write 13% humidity. We received 3.5" moisture last year, although our average used to be 18" before this drought started in '91.
Brownbag is right that block here seems to be the less costly alternative, the way it is looking. Now, to get one of the good builders to use it, that will be another pricky problem.
The moisture subject
CMU are very porus material. If it raining outside it can travel throught the blocks. For that reason it need to be sealed. Here on the gulf coast we get 58-70 inches per year normal but we have no winter. It will get below 30 for about one week and that only when we get a artic blast from up north. normal winter weather 45-60. Its 81 right now and the sun be going down soon. so it not high noon.
The mason I talked to explained about the right kind of block for this job and that there would be rebar in the concrete pad sticking out to put the blocks over and cement them to it for the walls, as there was for the well house.
Is there a reason you aren't considering plain old cast-in-place reinforced concrete? We find it competitive with block, stronger, and immensely more water resistant. With a proper footing, it solves the safe room requirement. When we started, poured walls were rare and I ended up forming my own. Now the majority of foundations here are cast-in-place.
The trade organizations seem to think that insulated concrete forming is the answer. I'm unconvinced.
We insulate the exterior of the walls and sheathe with sheet copper. I have yet to see a less expensive house built here. Or more maintenance-free. Last year we had an annual temperature swing of 10*(no heating/cooling), 65-75* but that's largely due to our earth cover.
I was raised in a concrete block house on the Arizona desert. We had major termite problems with all the interior trim. Entry probably was through slab cracks. PAHS Designer/Builder- Bury it!
---"Is there a reason you aren't considering plain old cast-in-place reinforced concrete?"---
Yes, the reason is that, although having heard of that building technique and of cast at the plant and moved into place, there is no one here that we could find that knew anything about it.
The only ones working with any concrete are that now missing ICF builder and this mason I just talked to.
Back to the drawing board, to do more research on that. We have two good cement companies here. Will call them tomorrow and ask about this.
You can't believe how little I know. Frustrating.
Termites have eaten many structures here but not this concrete block house or the attached red eight hole tile one. Talk about insulation! That red tile house, built in '36 and in perfect shape, cost the least of any to heat/cool or maintain.:-)
Out of the 138 homes I have "Framed" only 6 have been stick built. I live in Central Florida near the space center and everything here is block and stucco. Block is only run as high as the walls and trusses are fastened by means of an embedded metal strap in the poured tie beam. Typically ridgid styrofoam (3/4" panels) are placed against the interior wall and 1x3 strips are nailed over the insulation into the block using hard cased nails. I don't know the R factor of this but you end up with an air gap anyways...
On a two story home, the second floor is typically framed with 2x6 lumber. Guess block layers don't like setting up that much scaffolding ;-) The amount of clips,straps and other 'hurricane' related fasteners is paramount to construction and inspections here.
>I live in Central Florida near the space center and everything here is block and stucco. Typically ridgid styrofoam (3/4" panels) are placed against the interior wall and 1x3 strips are nailed over the insulation into the block using hard cased nails.
I'm seeing this exact setup right now from a builder's implementation of a design of mine. It frustrates me that this is the least efficient setup for energy, but I've not had luck talking him out of it. Sometimes people are conditioned to a certain way of doing things.
this is how I did mine.
blocks to peak
2x4 stud walls with r15
regular drywall
Just curious. How come you laid your block like that rather than in a running bond type pattern?
By looking at the following web page, I guess you did a "stack bond".
http://www.cmhpf.org/kids/Guideboox/brick.html
Matt
because I wanted to fill all the cell so by stacking this way the cell would line up. By running the other way a third to a half would never get filled due to wire, cells not open, etc. with concrete this way is stronger. without concrete the other way is stronger. I learn this from many many years of inspection filled concrete block wall for the school system.
>Typically ridgid styrofoam (3/4" panels) are placed against the interior wall and 1x3 strips are nailed over the insulation into the block using hard cased nails.
Insulation applied to the interior of walls indicates an assumption that the mass is only good for holding up the roof, not moderating the interior temperature. It's a small step for anybody who realizes that mass has something to do with interior temperature to understand that the insulation should go on the outside. Otherwise the mass is largely wasted.
Digressing to ICFs, I've seen outlandish claims for R value, up to R50, that further complicate any comparison. Some manufacturers lie. PAHS Designer/Builder- Bury it!
Otherwise the mass is largely wasted.
Ah yes, just drive through any of the pricer subdivision in Texas, and what do you see? Acres of face brick veneer required by covennant or HOA rules. (nowadays, the 12/12 pitch roofs have little or no overhang for shade, either.
Brick veneer has a thermal lag around 3 hours. So, around 1500, the east side in the shade has come right up to ambient--95°+ for July & August. You get home around 1800, and what's happening? That brick is now radiating that 95° heat at every weak spot in the R19 wall you live behind. West & South walls, out of the shade, hit ambient and climbed higher by 1500. "But all houses are like that, aren't they?"
O, to move that mass inside of the insulation envelope (and put culture stone/brickwork on the outside for the HOA) . . .
Or get 2" of spray on closed cell on the outside of those Florida houses (toss powdered borax in the foam mix to keep the bugs out, too)--what a change that would make.Occupational hazard of my occupation not being around (sorry Bubba)
Or get 2" of spray on closed cell on the outside of those Florida houses (toss powdered borax in the foam mix to keep the bugs out, too)--what a change that would make.
That, sans the borax, is what I was tempted to do to our 1911 structural brick building in Denver. It had great mass and no insulation. Instead we sold it, moved to the country, and built properly. Neighbors were probably relieved.PAHS Designer/Builder- Bury it!
Still think it would be some thing to try, you could sculpt all sorts of things in the foam, and then stucco/plaster over that. Be a cool effect, and the owners get a better home, too. Winners all around.Occupational hazard of my occupation not being around (sorry Bubba)
A house I designed is having that done right now. Well, instead of carving into the foam, they are adding extruded and molded foam to the foam insulation. One of the molded pieces is a carved horse's head in profile, be/c the owner is a horse nut. When they get pix, I'll show 'em.
Well, instead of carving into the foam, they are adding extruded and molded foam to the foam insulation.
Sounds like fun. And CapnMac is certainly correct. I have two families coming from Richmond tomorrow to see what this is about. You never know where any of this will go. But hey, they're bringing lunch and wine.
Don't forget the pictures. No telling what my deep- pockets (horse) barn guy might find interesting. Heard from his gofer today on another subject.PAHS Designer/Builder- Bury it!
>But hey, they're bringing lunch and wine.
Damn, I need a new agent. I've given about 500 tours, and maybe 6 have brought something. I don't ask or expect, of course. The one Breaktime visitor brought a 6-pack--we like those guys! Got a CD, a carving of a bear, and some plants. All nice and unexpected. Almost forgot, a couple visitors have brought a retainer!! Can't beat that. Have a good lunch! Got another tour myself tomorrow.
FWIW, I'm intrigued by the umbrella concept and am thinking it over.
Well, instead of carving into the foam, they are adding
Yeah, we were on the same page--I was just thinking of shooting on 2-3 extra lifts of 2" or so. Or, perhaps over some sort of armature. (Did have a flash back to the dome entrance thread a couple of months ago, too <g>.)
Ooh, a Gaudi theme would be so apropos for some houses I know in Titusville . . . Occupational hazard of my occupation not being around (sorry Bubba)
True, but couldn't the brick veneer Ruby intends be tight enough to stop them?Any jackass can kick down a barn, but it takes a carpenter to build one.
True, but couldn't the brick veneer Ruby intends be tight enough to stop them? [Termites]
All they need is a tiny crack and in they go, The brick has to have weep holes, which would be like a multiple lane tunnel for them.
_______________________
Albert Einstein said it best:
“Problems,” he said, “cannot be solved at the same level of consciousness that created them.”
Your mileage may vary ....
ICF is a good concept and a good idea around some parts of the county. The reason why I did not do it was. Termite love the form. Nobody here as every done it and if a form busted during the pour, oh well money down the drain. And all the extra material needed just to shore the form. Pump truck rental. Nobody sells the form around here, so large delievery charge. without brick on outside it still subject to damage from kid bicycle. But its a real good idea, and it is double the price of block
But I do like the idea
I thought about the weep holes, too. Not sure they're really needed in Ruby's climate, especially if there's a hip roof with a sizeable overhang and no wood at all in the wall. Of course, I know they're standard, but lots of things that are standard aren't necessary in specific applications.Any jackass can kick down a barn, but it takes a carpenter to build one.
a block wall thats not filled. You can bump and it will fall, only thing holding is a a little grout. The concrete is mainly impact resisitance not lateral load, but it does help. it not that much concrete . all of my wall to peak was only nine yards 5 1/2 if I just poured what required. An extra $200
Most building codes specify the allowable wall heights and spans, based on wind loads. I have designed hundreds of thousands of square feet of masonry wall across the country with hollow cells. Horizontal joint reinforcement, pilasters, and perpendicular walls support the lateral loading. You mentioned impact resistance, but you did not mention the cause of the impact. For interior walls the common design load of 5psf is enough to resist typical impacts that one would expect in a home. On the other hand, if you are worried about cars crashing into the wall, then more resistance is required.
All of my walls constructed without filled cells are still standing after 30 years, and the great majority of them are in industrial environments where the usage and loads are much greater than those encountered in a home. The secret is to construct the walls by code. The concrete alone does NOT add significant impact resistance.
i bump mine withthe jumping jack and it move the wall so I filled everything
Yes, was counting on using something on the OUTSIDE. No sense on using the block's mass to transfer heat/cooling out so nicely, as it is in this house now.:-(
Even then, it costs less to heat/cool than other similar sized wood houses around here, or let's say the bills are smaller. That may be a function of the dwellers having a broader range of comfort zones rather than the real insulation value of the houses.
That way of using foam was suggested by the mason, or something that sounded like that.<g>
The house will be on a slab. We already have the dirt work done, tested and passed at over 95. Ready for the concrete work. Floors will be all 12" tile, no carpets (allergies). Good idea on running the heath pump at night.
Ruby,
The commercial building that my business is in is all block. It has some type of granular insulation poured into the block and is VERY energy efficient. It is 3200 sq ft and my heating bill is not much more than the one at home. I was also wondering when we got away from brick and block construction and why ?
Bill
One of the types of granular fill used in block walls is vermiculite. Though it is thought of as not safe to use in some circles, it does quite well as an insulator! Here in the south we use it in schools and gymnasiums with great success.
Hope this helps,
JB.
I suspect labor cost is another issue. It wouldn't surprise me at all to find out that builders can't hire competent block layers at a price that residential customers are willing to pay.
I also like the idea of lots of thermal mass inside the insulation.
You may need to ask if the builders could build with "CMU" (Concrete Masonry Units, aka "Block"). "Cinder Block" is an older term for a very lightweight masonry unit using cinders as an aggregate. In some parts of the wolrd, the term "cinder block" will just get blank stares.
I like the idea of the block on the insode, especially in an "inbetween" climate like Texas can have (both summer heat & winter cold). I'd add a wrinkle, though--I'd use metal studs on the outside. Then use a "veneer" partition wall on the inside. That would give a good insulating wall on the outside, and a another insulating surface on the inside.
However, for that level of effort, you could just use ICF (insulated concrete form [block]). You'd use less concrete, but still have a strong, insect resistant structure. Now, to "do" an ICF structure, you really ought to use a concrete pump truck. That means you have to be in range of a pump truck (not too far out of a big enough town, in other words).
Florida still has a number of block-built houses, mostly to improve their performance against very aggressive termites. (Can be odd, seeing a detail with termite shield under the soffit, though . . . )
We used the "real" blocks in the well house, not the lighter ones.
When this building project started, talked to the ICF builder in town but he never got back to us and has disappeared. I think that masonry builders for a block house will be easier to find, especially since it is such a small, square house that we are not talking that many feet.
not the lighter ones
Ah, bingo! Thanks, you just reminded me of the specification term that was alluding me; the term of art is "Lightweight" block.
The downside to using Lightweight block is that you have fewer sizes & choices. A regular CMU comes in a bunch of modular sizes. They are also available in split face asn rusticated.
The recomendations from the Texas Tech study on tornado protection above ground seemed to prefer an interior room of concrete block, or metal clad wooden walls. After seeing Jarrel, I'd be real inclined to make my shelter below grade. I seem to remember that the Tech web site is supposed to have a link (somewhere) to the shelter construction guidelines. I can't find it, but it may have been on a different computer, too.Occupational hazard of my occupation not being around (sorry Bubba)
why not go with ICF blocks? You get better R value, faster construction and a more solid construction.
The brand ive used for ICF is arxx.
>why not go with ICF blocks? You get better R value, faster construction and a more solid construction.
According to the Oak Ridge National Lab, whose testing is the basis for the Model Energy Code, the wall that VaTom mentions--exterior insulation and interior mass--will significantly outperform an ICF wall.
Talked to these builders here and it will be next week before they get bids to me. GRRRR. They also don't want to cut the plans any, say that it is a really neat house as it is and would not save that much to cut a bedroom and such off but that they will take a good luck at where to cut, if they get the bid.
Anyway, I mentioned building with blocks and they say that they do that all the time in commercial buildings and will do so if I want to. They say it works well, makes great houses but cost twice on the electrical work because they use all conduit in the walls and more labor. Otherwise, the cost of such walls is close to wood framing. Nice to talk to someone that doesn't dismiss ideas out of hand but will think thru them.
Will decide on how to proceed when the bids are in and I am only talking to the one that will build.
That earth covered house is very interesting but, as it is mentioned in the article, still very much experimental. It would be hard to build here, on a high spot on the flat plains. Lot's of dirt to move in and not enough room around for it, with the barn and pens so close, I think.
Cloud, do you have a specific link or, if not, a citation on that? I did a web search and the article I found indicated that Oak Ridge found ICF construction to be 20% better than typical frame construction:
http://www.ornl.gov/sci/roofs+walls/research/detailed_papers/thermal/results.html
which was attributed to its "massive" wall construction, but would be interested in reading about a wall construction that is even better than ICF. The article above did mention that they had built four model houses and that those with "massive" wall materials (i.e. adobe, concrete masonry, or logs) at a 10% to 13% savings over 2x4 frame construction, but that didn't seem as high as they indicated for ICF.
>http://www.ornl.gov/sci/roofs+walls/research/detailed_papers/thermal/index.html
Same paper, it's in the details of the paper and the charts (chart 5, for example).
For example, here's from the summary:
"Comparative analysis of sixteen different material configurations showed that the most effective wall assembly was the wall with thermal mass (concrete) applied in good contact with the interior of the building. Walls where the insulation material was concentrated on the interior side, performed much worse. Wall configurations with the concrete wall core and insulation placed on both sides of the wall performed slightly better [than interior insulation only], however, their performance was significantly worse than walls containing foam core and concrete shells on both sides."
The best config is to put the insulation outside of the thermal mass. Not for nothing, but that's the exact config of the domes I design, and their low energy use comes from that much more than from any "domeness".
---"The best config is to put the insulation outside of the thermal mass"---
That is what the mason I talked to mentioned was best for blocks as heat and cooling savings, above the termite protection. Inside he suggested metal strips to hold sheetrock, spray insulation in the blocks and outside some kind of panel insulation, airspace and then brick, best I understood him. He seemed to say that thermal bridging thru the supports for the materials is minimal with the mass of the block. That is what his house and others he has built are like and he thinks are the best for our climate here.
I was considering using the fireplace's mass also for thermal mass, a little like the massive tile stoves we had in Switzerland.
I wonder how one could actual test the r factor of a wall. Not theory but actual run the test on a homebuild wall.
I don't see an advantage to spray insulation in the blocks. For energy advantages, I'd rather they be filled with concrete. Use the same R insulation outside as you would in a frame wall assembly to beat the performance of the frame wall by the amounts they suggest.
Ok. Will run that by them if we go that route. Thanks to all again.:-)
Ruby,
I've worked on dozens of block buildings commercially,and the 50 yr. old house I bought this year is block(except for a family room addition).You asked why more homes aren't built (outside the hurricane belt anyway)out of cement block and as Uncle Dunc pointed out,it is a labor intensive proposition.My dad was an electrical estimator and his first two rules were: 1.) Material is cheap. 2.)Labor isn't.That said, there is a very very wide range of masonary contractor efficiency based on equipment,crew and experience(and so price).There are some contractors I dread getting on the job with because they aren't organized and it's like pulling teeth to accomplish anything around them.On the other hand there a few contractors I dread just as much working with because they're so damn efficient I'm always playing catch up.Get buried with block construction and it is a PITA to recover.
I've read that most of the old vermiculite is contaminated with asbestos.My house isn't insulated but when I put a brick veneer on it I intend to have it shot with foam.I'll watch them like a hawk though and tell them ahead of time that if I find any empty cells they WILL come back and refill on their time.The last job I was on where they insulated the block walls with foam,the contractor did a terrible job.He drilled all the holes but rushed the foam.The customer added a few extras on my end and I had to fish MC cable down a couple of the exterior walls.In the cells that I fished they were empty the top two feet.
Speaking of fishing,if I were building a new house out of block I sure wouldn't put the electrical in the walls, like your "double the electrical price" contractor says.F that.Let them build the walls.Come in and rough the electrical on the surface.Shoot hat channel,insulate with ridgid foam if you want,and drywall.The only reason you would put the electrical in the walls is if you wanted a finished painted block wall.
My house was built by a man that took the Cold War seriously.Half of the basement under the addition has an 8" concrete ceiling in it for a bomb shelter.Two feet out from the house,in the driveway,is a manhole cover with a floor jack beneath it to get out of the shelter if the house gets blown away.
Barry
Edited 11/5/2003 11:06:00 PM ET by IBEW Barry
---" I sure wouldn't put the electrical in the walls, like your "double the electrical price" contractor says"---
I questioned him again on that, asking if we couldn't put the electrical wires in the baseboards or some other place that in the block, especially if they are coming from the attic to each wall.
This house has a flat roof, no attic and stucco directly outside and plaster inside so I imagine that the wiring, a thick copper wire covered with a woven cloth in places, looks like, is in the block, at least part of the way.
I really don't know enough about building to even think how to go about such things, will have to depend on them to know.
I will bring it up...
I think that all building techniques have their good and bad points. It is hard to decide what to aim for, will have to depend on what they are used to doing around here so they are up on how to and what has been working.
---"Shoot hat channel,..."---
What is that?
On the insulating, we don't seem to be needing any in the inside, the idea is to insulate the block from the outside, so the metal to attach the sheetrock is all that goes there, unless a water/vapor barrier may be needed inside too. Maybe there is room behind that, if the wires can be protected from nails?
Although we have a nuclear repository close by, we won't build a nuclear shelter, like you have, we will take our chances.
Now, tornadoes are another story.
What is that?
Hat channel looks just like it sounds, like a top hat (picture an upside down, flattened "U" with legs sticking out from the straight legs. It's metal, and you use a hilti fastener to shoot straight through the metal into the block. This gives a uniform 5/8" deep space in between the channels.
Any grief the electrical guys give for working in block walls will only be doubled or tripled by the plumbers--best bet is to keep the mechanicals out of the blocks.
I would not insulate on the inside of the block wall--I'd put all of the insulation over the outside of the wall. Having the block wall on the "inside" of the insulation envelope lets it moderate temperature swings (an important consideration in western Texas). How insulated? I'd install a non load bearing 3 5/8" metal stud wall 1" from the block wall, up to the soffit, where the ceilign insulation would then start. Values woulf look pretty good. The outside wall would be arounf R20, plus an 1' airspace, plus an 8" block wall, all before reaching the interior sheetrock. Around r 27, maybe. Not bad. no need for weep holes, either; the block is on the "dry" side of the wall. You get two choices on the windows. You can set them in the structural wall (the block wall), or in the insulating wall (the outside wall). Not much different, the best window runs to an R value of around 3, so the window is a break in the insulation no matter how you set it. Outside wall would be easiest to waterproof, though.
To get thermal mass from the fireplace, it has to be in the center of the building. An outside wall just means you have a solid thermal connection to the outside, hot or cold.Occupational hazard of my occupation not being around (sorry Bubba)
---"To get thermal mass from the fireplace, it has to be in the center of the building. An outside wall just means you have a solid thermal connection to the outside, hot or cold"---
Oh, yes, we were thinking of putting the fireplace against the safe room in the middle of the house, both used as thermal mass for the fireplace heat, but I am not sure we need to be that particular about that little extra heat, so we left those features out.
The house has porches on three sides and an attached garage on the N, so the water, little that it has been raining here lately, reaching the windows/doors/walls will be minimal. Porches are a small cost that is worth it in comfort, looks and protection of the structure in general.
Measured the sun's elevations to know how deep to make them on each side, to give some sun in the winter and shading in the summers.
I think it will be best to run all this by the mason and let him give the builder an indigestion with so much good information at once. The mason is the one that is putting some figures and plans together to see if using block is what we should consider doing here.
Ruby,
The previous description of hat channel is correct.It's the commercial standard for furring out block walls.When you use the 1 1/2"channnel (there's also 7/8"which doesn't help on the electrical) you can use regular 4"square boxes with plaster rings sized to your drywall thickness.You could use MC cable, which is just as fast as Romex to install,only because of the metal jacket it's safer.I don't know why you should have to be safer in a video store than in your bedroom, buy that's the difference between residential and commercial codes.You could use thinwall conduit stubbed above the ceiling for a raceway that would allow phone lines or Cat5e computer cable,or fiber optics,whatever the current generation is,to be pulled in or out.
What is your builder proposing to attach the interior drywall to anyway? If not gluing it to the block,hat channel would be a straighter alternative to wood furring strips.And no you don't have to insulate the interior,it's just that you only get one chance to add a little extra before the board goes up.
Your regular interior walls are going to be metal or wood stud aren't they?Block would be overkill,except for the saferoom.Your interior walls are where your plumbing would go,so I have no idea what Cap'n Mac is talking about.
Barry
Your interior walls are where your plumbing would go,so I have no idea what Cap'n Mac is talking about
And, I agree, interior walls are better. That being said, I've seen too much plumbing in exterior walls (4" stack cut completely through the stud wall, and almost touching the veneer face brick oustide, no less--nice ans flush on the inside, though . . . )
Liked your point on MC/Bx. It's probably a better application for a block walled house--and certainly will be better in the long run. When I was up in the Chicagoland area, all residential wiring had to be protected, EMT or MC in the late 60s--maybe that they allow thinwall plastic by now, don't know.Occupational hazard of my occupation not being around (sorry Bubba)
Using some type of furring to support the gypsum board is a good idea, whether it is wood or metal. The typical wood strips which are marketed as furring strips usually look more like a bowl of spaghetti. It is the cheapest grade of material that was apparently just thrown loosely on the sawmill floor for curing. So, opting for the metal strips is the best alternative.
The hat channels are typically 7/8" and "Z" clips are variable thickness. Whether the furring is 7/8" or 1 1/2", one must be aware of these limitations when hanging items, such as heavy pictures on the wall. The clear depth behind the gypsum board limits the type of fasteners one can use. Toggle bolts can get up to 3" long and molly bolts can get over 2" long. I have found a good alternative with a 3M product that adheres to the wall board and can be removed by pulling on a tab, leaving behind no residue. Research the 3M website, because there are several styles and weight capacities from which to choose.
Ruby,
Just a completely unrelated note about your plans to alter the plans. If you have to get a building permit, they will base the cost of that, and your future taxes, off of the drawings you submit. I'd suggest that any changes you want to make in square footage be done before you submit the plans for review - it could save you a whole lotta dough that you'd rather put into your home.
---"If you have to get a building permit, they will base the cost of that, and your future taxes, off of the drawings you submit"---
The tax appraisal office is the first place I went with my plan to see what taxes on it would be, long time ago.
We are in a rural area, the nearest neighbor several miles away. The only permit necessary is a state one for the septic system and that is automatic here.
Still, the builders that are submitting bids are members of the local builders association and abide by their code of ethics. It requires that they build all houses up to code as a minimum and that they have an absolute guarantee to their houses for 10 years. They cover themselves with similar guarantees to them from the subs. I asked.
That guarantee is why they are careful how they build and why they won't change to a new or experimental technique too easily. Of course, cement block is everyday stuff in commercial construction here so that would not be too difficult to consider for them.
There won't be any review of my plans by a building board but since an architect approved them, they should be at least safe and reasonable, I hope.
"The only permit necessary is a state one for the septic system and that is automatic here."
Some areas base the required size of the septic on the number of bedrooms (don't ask me why), so if you are knocking off a bedroom that could affect this 'automatic' item as well.
Ah the bliss of not gov'ment having folks tell you what you have to do on your own property.
---"Some areas base the required size of the septic on the number of bedrooms (don't ask me why), so if you are knocking off a bedroom that could affect this 'automatic' item as well. "---
Wondered about that too, why. Maybe three bedrooms means more people may be using the facilities, needing a bigger system?
We have two bids on the septic system, one on two bedrooms and one on three.
It is a little different for each. We have a good slope on the S yard toward the main barditch on the road that goes N-S in the front, E side, of the house. Good percolation and the water well is 1/3 mile N of the house.
"Two feet out from the house,in the driveway,is a manhole cover with a floor jack beneath it to get out of the shelter if the house gets blown away."
Just have to make sure that no one parks over it <G>.
I have considered for quite some time building a home of CMU, with a 6" bearing wall on the inside, and air space and 4" CMU on the exterior. Then I planned a Frank Lloyd Wright trick of striking all vertical joints flush and raking all horizontal joints.
I have seen several in this thread recommend filling all the cells with concrete, but I don't understand why.Sure the concrete would add mass, but it would not add much structurally. You would need to add some steel in those cells to resist any lateral load. Even that may not be necessary if horizontal joint reinforcement is used.
I had planned to use ladder type joint reinforcement which would bridge across from the interior wall to the exterior wall. I would also apply a vapor barrier to the air space side of the interior wall and fill the air void with polyisocyanurate foam boards.
One thing to be aware of is zoning regulations or neighborhood covenants. Most neighborhoods require all CMU to be out of sight.
For the gable end, some other material is often used, but CMU would be a good material, especially if the roof slope is 6:12. At that slope the blocks could be cut diagonally and both pieces used.
As for filling the cells with a granular insulation, I was permanently affected after visiting a jobsite where I had specified such insulation. All the cells on the site had been filled, but the electricians had not completed their work. So, when the hole was cut for an outlet box, all the insulation from the hole height to the top of the wall spilled onto the floor. Do you think the electrician replaced it? Also, the granular fill compacts itself over a short time and could leave as much as 4" of uninsulated cell at the top of walls, window sills, etc. For all the effort, I feel that granular insulation filled cells are just not worth it.