I’m do a two-storey addition (small footprint <500sqft) design and set of permit drawings for some friends who want to do most of the build themselves. There is an existing addition sitting on an existing concrete block foundation that will have to be removed (an old DIY job and an example of what not to do). I’m used to drawing for professional builders doing the building.
I’m wondering if people have any opinion about what is the best/easiest foundation for a DIYer to build. The husband has done other work around the house and does have a good attention to detail, but no experience building a foundation or any experience with concrete (as I understand it). I’ll make sure the drawings and specs are really clear and detailed, but still I’m wondering what the best system would be to start with.
Any and all suggestions/comments appreciated!
Penny
Replies
I would go with a monolithic slab with integral turned-down footings at the edges. Use 1X2 pour strips about the outside to indicate level.
The slab with thickened edge is a good choice. If you don't want the slab or need a deeper foundation then ICF's are pretty straightforward.
slab foundation
Should gravel be compacted in a trench to below frost. Is it wise to form footings on top of this at grade level? Pour footing first, then form for your slab? Rigid insulation? pex tubing for in floor radiant heat? Then pour slab? I'm just guessing with my limited experience so please help..?
DYI foundation
Get some professional help / advise / inspection etc. Concrete can be very unforgiving. It likes to bulg or blow out forms and it waits for no one.
Big worries
That's what I'm worried about. I can make the drawings and directions very detailed and there will be an engineer on top of that, but for cost reasons they want to do the building. Should I be recommending ICF? I know they want to be economical but I'm looking for what are the real issues that I need to be thinking of for drawing for a DIY project.
That's what I'm worried about. I can make the drawings and directions very detailed and there will be an engineer on top of that, but for cost reasons they want to do the building. Should I be recommending ICF? I know they want to be economical but I'm looking for what are the real issues that I need to be thinking of for drawing for a DIY project.
No matter what type of foundation you come up with, you still have to draw it the same way you would for a professional. It has to be built the same way no matter who's doing it. I don't understand what you want to know. What is the problem? Is it that you want them to build an easier foundation? What foundation will be easier for someone who's never done one before?
Drawing for DIY
I will draw standard construction documents (what anyone would draw for a professional) but I absolutely think that construction documents can be made more clear for someone who isn't used to reading them and flipping back and forth between sections and details to figure out what's going on. I'm working on a BIM model in Revit that should be easier to generate some 3D views and make some things more clear, especially at connections and openings. When I get more done, I'll upload some images.
And to your second part, yes that is what I'm asking... is there such a thing as an easier foundation for a DIYer? Considering how much truly skilled labour has dropped off in our generation I was hoping some manufacturers were taking that into consideration in design new structural systems. I expect there is still plenty he would need to understand before starting and he has friends in the building trades that have said they are willing to help out some. In my mind that is still a DIY project if you aren't hiring specific trade contractors to do their thing.
foundation
Form follows function
Tell us more about the WHOLE project. Location, building codes for the locality, slab on grade? crawlspace? basement?
What kind of addition? Access?
Access...Good question
There is no laneway access and the addition is at the back of the house. It is a downtown detached 2-storey house on a tight lot meaning it's got about 2' clearance on one side from one house and 5.25' that narrows to 3' at the addition at the back on the other side. There is lots of room at the back, but you couldn't have a truck pouring concrete, for example.
The existing old addition is sitting on a full height basement concrete block foundation that is of questionable structural value. We are getting an engineer to look at it but from my experience it should be replaced. The new foundation will need waterproofing and preferably exterior insulation.
Keep in mind that a pumper truck can probably reach over the house, if it can get close enough to the front.
But if you can't reach it with a pumper then you'll probably have to go with CMU.
Gonna be a major PITA schlepping all the materials back there by hand.
Pumper truck
That's something to consider. I don't suppose you have any companies that you recommend with good support for DIYers that work in the Toronto area? (are there any smileys anywhere?)
This one goes under the heading of "if you need to even ask, pass it on to a pro."
Most places would require foundation drawings to be signed by an engineer, or the licenses contractor who is actually doing the work. Doing drawings for your friend to present as his own is a crime- for both of you.
There are reasons for this unforgiving attitude. "Holmes on Homes" has had a few episodes where someone tried to fake their way through foundation work.
There are two 'detauils' that can't be avoided. The first is that there WILL be serious digging involved, even for a slab. The second is that there needs to be a LOT of attention paid to tying the two foundations together.
Finally .... are there any trees nearby? It simply won't do to have tree roots split the foundation a few years down the road.
This is a bit strong
Most places would require foundation drawings to be signed by an engineer, or the licenses contractor who is actually doing the work. Doing drawings for your friend to present as his own is a crime- for both of you.
I'm sure if you would study every AHJ you might come up with wording from some that supports your point, but my experience doesn't confirm your statements.
While a homeowner could be over their head in most any phase of construction, many if not most bldg insp. operations allow diy work including the general permit drawings. Where engineering questions come into play the individual will have to produce stamped drawings, supporting calculatons or even structural designs done by suppliers such of truss, lvl, and engineered lumber.
Wooha Nellie - What unqualified person?
I'm fully qualified for residential home design here in Ontario. BCIN and E&O insurance and all. And I never said I was doing the drawings for my friend to present as his own. I will be submitting the drawings on their behalf and the structural will be supplemented by a structural engineer. I thought that might be evident in the part where I said I'm usually doing drawings for qualified professionals to do the building. Sorry if there was any confusion. And I'm sorry for the lack of details.
The project is in Toronto downtown and the existing foundation that is under the addition currently is a (nearly) full-height basement. They don't want to go any deeper even though the husband is a tall fellow. They don't intend to use it as habitable space, just secondary storage. And we are meeting with an engineer to get a professional opinion on the structure and exterior wall that the rest of the new addition will go against.
And no there are no trees. The existing foundation is a mess all on its own from the last DIYer who built it.
What I'm really wondering about is the pros and cons for various structural systems when they are left in the hands of a DIYer, such as poured concrete vs ICF or anything else you might suggest.
It's interesting that this question came up because I've often thought how I'd do it if I had to build a foundation.
Once the excavation was done and you were down to undisturbed soil or very well compacted soil if it had been previously "disturbed", obviously, you'd have to know the bearing capacity of the soil but once you did you could calculate the size of the footings and form them up, place rebar and pour the footings (I'm assuming your clients would not be opposed to ordering concrete vs mixing it by hand). Once the footings were done I'd seriously consider using a drystack technique with concrete block and then using Surface Bonding Cememt. If you did, it would have been good to place the vertical rebar in the footing for the cores before the crete set up.
See here http://www.drystacked.com/forum.html
Of course this is all moot until we find out what the frost depth is. (Opie, are you there???)
Re dry stacked, in Denver about 15 years back I worked on a "build" (can't recall what organization) where special block were used for a dry-stacked structure that was then "grouted" with pumped concrete. The special block had tongue-and-groove mating surfaces (like ICFs) and were pre-finished on the outside. Generally about 4 feet of wall would be set, grouted, and then another 4 feet set. An unskilled crew could do a house in two days this way (starting from a foundation), with only one or two "skilled" people to direct things (and their skills need not be substantial).
Of course the technique was lousy from an insulation standpoint, so ICFs, etc, are probably a better choice in most areas of the country.
I believe Amish was referring to an unqualified person doing the drawings for the DIY to submit. It's a fine point, but only the DIY can design the DIY's work The only folks who can let others use their designs are appropriately licensed architects and engineers. A contractor can only design for his own work. Someone without any of those licenses can only design for the house they actually own and live in.
I see ads on Craigslist all the time, asking for licensed folks to pull permits for them. What the OP proposes to do is no differernt: he does the paperwork, and the DIY does the work. That's not allowed. It's fraud.
You guys are filling stuff that is not there
I don't know where you guys got the idea that I wasn't qualified or that I was going to give the drawings to my friends to pass off as their own. I'm qualified and insured and will be submitting the drawings.
Do other people do work for DIYers and what are the pitfalls that you have to watch out for or what are the easiest systems to build that don't depend on the precision of a professional builder? Is insisting that they go for ICFs being too pushy and paranoid? Or are there other systems that are also easy to use that I haven't come across. My work generally is for owners who hire contractors not owners who want to build the thing themselves.
The project is in Toronto. The footings have to be below 4 feet. The existing basement foundation to be removed is already well below that at roughly 6'. The soil is sandy. This downtown portion of Toronto is built on what was a lake bed in the last ice age. The husband is reasonably fit, I guess. ;)
Well, if he's really going to do the foundation himself then ICFs are probably the obvious choice.
You basically have 3 choices:
ICFs
CMUs
Poured
DIY foundation
In any case this is a permit situation
If the municipality accepts the drawings you can proceed from there
They might accept, reject, correct or otherwise deal with it. Minor faults are usually pointed out (re-submission possible)
Quite often they issue local requirements and approve the plans if they meet their standards
The second issue - doing it yourself - is another page. A good proper foundation is a MUST. If you have never done one get a professional to do it. Saves money in the long run.
DIY primary goal is to save money. On the first foundation in your life my guess is it will cost you a LOT more
Not worth it unless you want to become a foundation contractor. In that case hire on a construction crew and learn
DIY foundation
Just another comment/thought: Since you drew up the plan
What DID YOU spec in the plans?
Woodfoundation? ICF?, blockwall?, concrete?
Still on design development
I haven't specced anything yet. I've done the existing conditions drawings and we've run through a few design options for the kitchen/new bedroom above. Now we're on to construction system issues and this is the big question. Poured concrete is probably the cheapest. Getting permits for a wood foundation here is just way to much of a headache. They can see from their old foundation how concrete block can go awry.
So, are there ways to make poured concrete easier for a beginner or should I push them toward ICFs? or something else innovative that I haven't thought of/heard of?
Heck, Toronto's south of here, and CMU foundations work out fine here. (Of course, it depends to a degree on the expansivenes of the soil -- dunno what the soil's like in Toronto.) What can be done, if there are concerns, is to run rebar down about every 4th core and pour concrete in after it. This makes the wall probably about 4 times stronger (but of course requires a moderately substantial amount of concrete).
But I really think you should encourage the guy to contract out the foundation. That would save a lot of wear and tear on both of you.
(One important point is that having the foundation be "true" is critical to the success of the rest of the project. It's hard enough to get it right when a pro's doing it, but harder still with a novice who has no experience with foundations.)
No argument about CMU from me
No argument about CMUs when they are built by a professional, but you should see this existing foundation. You hit the nail on the head with the comment about how it needs to be "true". They are really tight for cash so I think it is highly unlikely that I'll be able to convince them to contract it out and the husband enjoys the DIY so what am I going to do?
Are there the same issues with ICFs or are they easier for the less skilled to fit together and lineup, etc?
Filled Cell interlocking CMU
I'd recommend interlocking CMU, with the cells filled. Locally I can get units that are tongue and groove, and stack just as easily as ICF, and cost less unless you need the insualtion value of the ICF. They are designed to be pretty novice freindly. But, most of them do require some form of sill to start from, and it will need to right or the whole thing is a mess. But, that is also true of icf.
There are several manufacturers who have systems available in Canada.
Look at Azar, http://www.azarblock.com/producers/prodlist1.html
There is a decent overview here: http://web.dcp.ufl.edu/stroh/CMU-Systems.pdf
diy foundation
If you are looking for ICF check http://www.arxx.com. These probably will be the easiest to assemble. It takes still skills and experience no matter what. The first ICF we did looked like a child's play "just like Lego" we were told. "it will go up in no time flat". Several weeks later we still had problems. (those ICFs were not arxx). We learned alot with the system but this is not applicable for a one time DIY. (who would have thought that windcondition shifted everything out of square, fighting bowed walls or lifting ICF forms during pour is not for the faint).
Pumping to the back can be done with a line pump, it does not have to go over the house. Depending on the length be prepared to loose concrete in the line (order more than your wall requirement).
IMHO this is not the time to pour concrete (DIY on top) in Canadian winter. With an open basement/excavation frost protection is a different subject.
If the funds are that short maybe reconsider the whole project, otherwise get the building done to lock-up stage professional, maybe even drywall and then do your own stuff
Caution about wind
Thanks, I will check them out and that is a very helpful comment about being aware of wind conditions. I certainly was wondering just how easy various ICF systems are or even ICFs generally. Really the goal is to find the best place to start. And thanks too for the tip about the line pump.
Don't worry, none of this will be done in the winter. The permits will likely go in the end of Feb/beg of March, for work to be done over the summer. In the end everything will be re-assesed when we have fully detailed drawings to be reliably costed, but for now we are assuming an owner-built project and researching if there are any preferable assemblies that lend themselves to that kind of thing. Other than that, he's a careful worker. I've seen some of the things he's done around the house so far, so it might be a slower process, but I think with the right amount of planning and preparation it should be possible.
diy foundation
building in above freezing condition will be of great advantage and saves tons of money.
If the client is determined to do it himself, I would recommend he looks for an experienced "helper" to work with him. Maybe someone who recently retired, pay him on an hourly basis for time he really needs him. The retiree would not mind short hours but can provide quality advise and "how to" (ad in craigslist or kiji or local paper)
ICF companies provide training sometimes but nothing beats the person on site who knows how it is done. ICFs can become very difficult depending on the actual building lay-out. Likewise the concrete supplier must have experience placing concrete in ICFs. (how can you verify that concrete is placed all the way down to the footing? No voids?)
Ah, concrete is so unforgiving coming back to the wind: any idea how much pressure there is on a sail 30' long, 8' high even in a mild breeze?
Qualified helper
Finding a qualified helper is a good idea, though making sure they are qualified is the tricky part in this mega-city where everybody seems to have an opinion and think "oh yeah! I can do that/help you with that!" [The down side of the can do attitude! ;) ] But really, with enough asking around I think that should be possible.
And I'm really getting the picture of the wind....
Dry-Stacked CMU
Thanks, Jigs-n-fixtures for the link to the dry-stacked manufacturer and help site. That is definitely something I will look into. DanH also mentioned that system earlier in the thread with a comment on how easy it was, but with a caveat about insulation and Fingers put a good link in his post to forum discussing dry-stack. Looks like the forum had to shut down due to spamming issues but there is still quite a lot to look at.
Thanks a lot everybody, this has been really helpful. I have to get some work done now, but I'll check back again later in case there are any more ideas.
Cheers,
penny.
Yeah, I helped out on an interlocking CMU build in Denver about 15 years ago. Most of the labor was high school students, and a few semi-skilled types. The hard part is starting right and managing doors and windows.
Of course, the interlocing CMUs need to be "grouted" and will use more concrete than ICFs, I suspect. So I don't really see any advantage vs ICFs.
Starting a project
Very good point about the beginning. I can see if someone wasn't thinking really carefully they might say to a helper, we'll get started and then you can come and see how we're doing. Clearly the wrong approach generally with starting any new stage of construction, but especially in the case of dry stacked or ICFs or any kind of block or masonry construction, where undoing and starting again would be a real PITA.
You guys are all great.
If you're licensed to do this, more power to you.
I believe your area requires 4-ft. deep footings I do NOT reccomend bricklaying (or block laying) by a DIY, especially in this season. There's a fairly limited time the mortar can sit idle between work sessions; you don't want to stop and resume a week later; it pretty much needs to be done continuously from start to finish. ICF's, OTOH, are much more tolerant of the novice builder. Or, so it appears to my untrained eye.
Personally, I think a concrete footing, and slab is the way to go. Let the DIY play with a bobcat and ride the thumper- then have a concrete crew do their thing. Time - and wet cement - waits for no one.
Simpson Strong-tie is one maker of connection systems, and has plenty of information about tying a new pour to the old one. Don't skimp.
Another detail to watch is the UFER, or grounding electrode. Chances are you'll need to put one in the pour, and tie it to the existing ground rod.
Does Ontario have an enegy code covering new construction? In Nova Scotia, any new foundation is required to be insulated to R22. The easiest and cheapest way to achieve that is with ICF's.
come on over to Breaktime Classic. We've just begun a discussion of first time ICF construction.
http://forums.delphiforums.com/breaktimeclass/start
My opinion on what type of foundation is the best and easiest for a DIY with no concrete or masonry experience, is the one contracted to a professional. No disrespect meant, but "a mans gotta know his limitations". Poured concrete with proper details as specified by you. Foundations are not a place to learn (or be cheap).
I am a very capable DIY with over two deacdes in contruction related fields, but I am not a contractor, a builder or a construction worker. I can do most of the tasks involved in residential construction, with the exception of smooth, flat plaster (those guys are magicians!) The main difference between competent DIYs and professionals is proficiency and tools. (Notice the qualification) I know how to do concrete work and I am certainly capable, but I do not have the tools, forms or profeciency to do the work to my standards. I contract out concrete work also because I don't like to do it, and my time is better spent building on top of a well done foundation or slab. I would dig the hole and do the other grunt work for the professional, just for the fun and exercise of it.
Just my opinion. Take it for what its worth. BTW, you've heard a lot from some vocal and prolific posting people with no or very little experience outside of flying a desk, BEWARE.