After way too many years of research and asking way too many questions in here, we’ve finally grabbed a loan and are going to finish our basement.
The gas insert for the fireplace is already on order, so no turning back this time. ;o)
So…I need a recap on some quick tips/tricks for the project.
I’m going to be using 1″ or maybe 1.5″ XPS foam up against the foundation wall, 2×2 metal studs, then the Densarmor Fiber-glass faced sheetrock. For most of the walls. One wall I’m hoping to use thinner XPS with sheetrock adhered directly to it on the upper half, with built-in shelves below (This is the wall with the fireplace).
The questions:
– XPS glue. What should I use to glue the XPS to the walls? (walls are painted cement block)
– Sealing the sheets…what should I use to fully seal the XPS from the wall? Tape? I was thinking of leaving .25″ gap between each and the floor, then, once all glued, come back with spray foam and seal all around each sheet for a complete seal against the wall.
– Gluing sheetrock to XPS…is that a viable idea? It’s be the upper 4′ x 4′ of two parts of the wall that I’d like to glue sheetrock directly to the XPS. This is to keep that wall from being too thick as I want the fireplace to not be swallowed up by the wall.
– Code. I’m almost positive code around here requires plastic sheet vapor barriers in basement remodels. I really want to avoid this and go with the building science recommendations these days. Any tips on convincing the powers-that-be that this is OK aside from showing them the publications that recommend this method (maybe that’s all it takes?)
– Sole Plate attachment. Is it possible/viable to attach a metal sole plate to the concrete floor directly? Or should I go with a wood plate? I assume if wood, I should use treated, in which case what’s the best way to separate the wood from the metal (to prevent corrosion)? Felt? Add a non-treated second plate?
– Any suggested consumer-grade tools for working with the studs? Sounds like powered tin-snips would be useful.
– We have steal i-beams in our basement and we’d like to keep them exposed (going for a ‘loft’ feel). I’d like to run the partition walls up to the bottom of these in some places, as well as mount some pocket doors. Any suggestions on a) metal strapping to hold the top-plate and b) any industrial/agricultural track-door hardware I should look at?
Thanks!
Replies
I just learned a technique at an ICF (PolySteel) seminar. Use one side of their "expandable" form, and just glue it to the concrete with their foam2foam glue (better GreatStuff).
This gives you 3" termite and fire-resistant insulation, vapor barrier, internal furring strips to screw on your rock, and it's easy to hot-knife in wire and electrical boxes.
One product.
Forrest - pimpin' for PolySteel
Interesting idea. I'm looking at their site but can't find that specific product, though. What's the cost on these?
http://www.polysteel.com/psform_polypro.htm
This stuff. Don't know about pricing.
Forrest
I'd recommend using full 3-5/8" studs for framing, whether you use metal or wood. Much easier to work with as far as your electric boxes, plumbing, etc. And you can use regular batt insulation. I do residential and commercial drywall and prefer wood framing on residential. Easier to fasten doors, trim, etc. I assume the XPS you refer to is a type of foam insulation? I don't think it's feasible to glue sheetrock to it, though I can't say for sure. Never tried it. Again, what do you attach trim to without some sort of framing? Can't you move the fireplace out to keep it from getting "swallowed up"? Fastening track (or top and bottom plates) can be done with a powder actuated tool available at the local HD or Lowes. Pins are made for fastening to concrete or steel. As far as the powered snips or shears, I've never used them. Manual snips work fine on light gauge metal or you could opt for a "chop saw" and have the capability of cutting a whole bundle of studs at once. A cheap one from someplace like Harbor Freight should run less than $100 and be adequate for the job. As you stated, the vapor barrier would be up to the local inspector. One last note, Dens Armor has a rougher "texture" than regular sheetrock face paper. You'll find your joints, once finished and sanded will be much smoother. If you're going for a "slick" finish, you'll want to "glaze coat" and sand the entire wall prior to paint.
I really don't want wood down their. I figure why give mold any surface to grow on given the chance? ;o)As far a trim/mouldings...I'd screw in if I need to, but there won't be any door jambs or anything so there's not going to be much beyond the floor trim.XPS = the pink stuff. I'm going with the Building Science Corp's method of using the XPS as a permeable vapor barrier (Which, now that I think of it, will probably meet the needs of local code...I hope. It is, afterall, acting as a vapor barrier).As for the fireplace, this is an immovable object. A few tons of brick. and supports the fireplace above it. ;o)The chop saw is a great idea!As for the densarmor texture...that's a great point. I did our bathroom with it and did notice that issue. Most of the joints were covered with a pseudo-chair-rail in the bath so it wasn't as noticable. Hmm...yea, that sounds like more work now. ####. ;o)
I understand your thinking. A little glue and a few trim screws should do it on the base. Glazing the Dens Armor can be done fairly easily. Thin your mud with water to the point you can roll it with a long nap roller. Roll an area (maybe 4' x 4') then wipe off with a broad knife (10" or 12"). Do the whole area, let dry, then sand. May take a second coat. You can apply the mud with a broad knife, but a roller is faster on a large area. The mud you wipe off can go back in the bucket, but you'll have to re-stir and add a bit of water from time to time as the sheetrock will absorb a lot of the moisture. I also understand what you're saying as far as the fireplace. I was thinking a "freestanding" or insert.
Good luck.
The yellow handled aviation snips will cut the metal studs very easily, and you'll have more uses for them down the road than for a powered chop saw. get a good brand, not the chinese stuff, and they will last you for many years.
You can buy a ramset gun for about $25 at Lowes. It is a single shot, only does .22 loads rather than .27 and only goes up to about load #3 but it will work great for a small job. You have to smack the back end with a hammer to shoot it, no trigger, but the price can't be beat.
"Put your creed in your deed." Emerson
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
Is it OK to fasten the steel stud directly to the floor? Would I need any sort of break between the two? I'm assuming you run the risk of wicking moisture and rust if it's directly in contact with the floor...or am I being paranoid? ;o)
The studs and track are galvanized. You can cut pieces of 2x4 to fit between the studs and shoot them through the bottom track to give you something to nail trim to. As long as you hit it straight, a 16 ga finish nail will go right through the track. Same for door jambs ... fit a piece of 2x4 into the metal jamb studs and the door frame will have plenty to fasten to."Put your creed in your deed." Emerson
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
"Is it OK to fasten the steel stud directly to the floor? Would I need any sort of break between the two? I'm assuming you run the risk of wicking moisture and rust if it's directly in contact with the floor...or am I being paranoid? ;o)"If you have that much of a moisture/water issue you should not be finishing the basement.Yes, I think that you are bein paranoid.Also DAP is HEAVY, HEAVY, HEAVY.USG was at Lowes appreciation days and I was talking about DAP. They make a Mold Tough gypsum panel. It is a green board, but has more than just water resistant. It has mold inhibitors in both the paper and the core.HD has the Mold Tough.Here is a sight where they are pushing there material.http://www.getmoldfacts.com/Note that they main point is water and moisture control, which is needed reguardless of the products used.I did a friends basement using 2" XPS. The foundation had crack. That had been patch and engineered supports. But it have an 8" differece from top to bottom.so I used PL Preumum blobs to spot place the foam. on the parts of the foundation that was most vertical. Then used Greatstuff to seal top, bottom and side to side.For the walls against the foundation I used 1 5/8" metal studs. In the bathroom I where I had to divide it off from the rest of the basement I used 3 1/2 metal studs.But where I put in doors I used wood studs or inserted wood into the stud channels. While I like working with the metal studs, being used to working with wood that found using it at doors made it much easier than doing a pure metal system.And the wood won't be in contact with the foor so their shouldn't be a problem. But if you want you can treat it with Trimbor or similar.A friend of mine that does commercial tenet finish showed me how to do the metal track. He used had a cordless pin nailer to install the bottom track. What I did I used tapcons.With the lightweigght studs and track you can use a metal snipes to cut the side. Then a utility knife to score across the flat "backside". Then just bend the stud back and forth and it will break..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
"Also DAP is HEAVY, HEAVY, HEAVY."I know. And ITCHY! And our house is about 12' off the sidewalk, so I need to haul this up 12', through the house, then down 9' to the basement. Not looking forward to it. ;o)But...for peace of mind? Maybe it's worth it? I'll look into the other stuff too, though. For the record, the basement is dry from external water. We've regraded the outside and added a new patio to the other side and we haven't had any water issues at all. The one area we used to have water problems has been dry for a while, but isn't part of the basement that will be finished anyways.The bigger issue is humidity...it gets REALLY humid down there in the summer, so want to seal the walls from condensation. We do run a dehumidifier as well.Your method sounds pretty much like my plan. Thanks for the tips!
Basements have the same general level of MOISTUE in the air as the upstairs.But the air is cooler so that the RH is higher.The insulation will help warm up the basement and drop the RH. Might still need a dehumdifier on the worse days, but the just insulating helps a lot..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
The insulation will help warm up the basement ....
Bill, may I correct you and point out that the insulation will slow down heat transfer to or from the basement? Insulation by itself doesn't heat or cool anything.
I know you knew that but people who don't might misunderstand what you meant to say.
Your point about the RH rising as the temp drops is excellent, and that's one of the main reasons I don't think the OP should be using metal studs down there: condensation happens a heck of a lot easier on metal studs than it does on wood.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
Like this ...
View Image
"Put your creed in your deed." Emerson
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
So many questions, so little time to answer them all....
XPS glue. What should I use to glue the XPS to the walls? (walls are painted cement block)
View ImageUse this stuff: PL300 It's made specifically for XPS panels.
- Sealing the sheets...what should I use to fully seal the XPS from the wall? Tape? I was thinking of leaving .25" gap between each and the floor, then, once all glued, come back with spray foam and seal all around each sheet for a complete seal against the wall.
Sealing the foam to the floor is okay. Buy a foam gun. http://www.touch-n-seal.com/foamguns.htm
Do not space the panels apart laterally; use the shiplap edges the way they were designed to be used and tape them with Glasclad tape (the red stuff).
- Gluing sheetrock to XPS...is that a viable idea?
As an idea, it's bad. If you insist, use PL300, but don't be surprised if it sags over time. XPS is not structural, and gyprock isn't wallpaper; it's heavy.
- Code. I'm almost positive code around here requires plastic sheet vapor barriers in basement remodels. I really want to avoid this and go with the building science recommendations these days. Any tips on convincing the powers-that-be that this is OK aside from showing them the publications that recommend this method (maybe that's all it takes?)
XPS qualifies in some areas as a vapour barrier but I do not know the code in your area so you'll have to check with the AHJ. I agree you would be better off with foil-backed kraft VB to let excess moisture out, but if you aren't allowed to go that way, you'd better plan on installing an air-exchanger to keep the air fresh in that basement.
- Sole Plate attachment. Is it possible/viable to attach a metal sole plate to the concrete floor directly? Or should I go with a wood plate? I assume if wood, I should use treated, in which case what's the best way to separate the wood from the metal (to prevent corrosion)? Felt? Add a non-treated second plate?
Metal in direct contact with a concrete floor slab is a bad idea as it will rust out over time due to condensation moisture. This is not an issue with wood, so use that instead. You do not need to use treated wood which will introduce nasty organic poisons into your residence; lay a 6½"-wide strip of 15# felt centered under the plate and Ramset or TapCon right through it. Fold up the 1½" of felt left on each side and staple to the edges of the plate.
- Any suggested consumer-grade tools for working with the studs? Sounds like powered tin-snips would be useful.
Electric snips are expensive and heavy; pneumatic snips require a compressor. However you can cut steel studs on a CMS with a standard carbide-tipped framing blade, but wear ear protection, gloves, and a face-shield while doing so. But see above; I see no reason you shouldn't frame with wood, use ordinary gyprock, and simplify your life. The mould issue has been seriously exaggerated by manufacturers with anti-mould products to sell. You are looking for 'The Little Man Who Wasn't There.'
- We have steal i-beams in our basement and we'd like to keep them exposed (going for a 'loft' feel). I'd like to run the partition walls up to the bottom of these in some places...
Drill through the topplate and the flange of the I-beam and through-bolt the plate to the flange. ¼-20's ought to be big enough; they're heavier than 20d nails, after all. Use big washers on the wood side to keep the bolt head from sinking.
If you insist on using steel framing, braze or tack-weld the top plate to the flange.
...as well as mount some pocket doors. Any suggestions on a) metal strapping to hold the top-plate and b) any industrial/agricultural track-door hardware I should look at?
Install a 2x header under the flange of the I-beam with ¼-20x2½" machine screws and nuts on 16" centers. Do not drill into the web; drill only through the flange. Make the header 3½" wide (assuming 2x4 framing for the rest of the wall) by twice as long as the doorway is wide, plus 6 inches. Mount the track to this, as well as the split studs on both sides. Don't go to agricultural door track unless you are planning on hanging blast-doors for a bomb shelter. Just buy a standard pocket-door hardware kit.
Dinosaur
How now, Mighty Sauron, that thou art not brought
low by this? For thine evil pales before that which
foolish men call Justice....
Thanks, dinosaur.I agree on not wanting the treated wood down there. But, having a non-treated wood sole plate seems to defeat the purpose of using all the metal studs. BUT...I'm agreeing with you on the mold being 'over sold' as an issue, too. I probably am being overly paranoid.Welding studs to the i-beam = an excuse for me to get a welder!
Another option for basements is to use Trex as a sole plate, but it won't give you the same thermal break with steel studs as using foam.
Billy
Glue the XPS foam to the walls with PL polyurethane glue. I caulk and tape the joints. Use spray foam to seal any gaps.
I like 1 5/8" 20 ga. steel studs. They save space over the 3 1/2 inch studs and the 20 ga. steel is strong -- not flimsy like some steel studs.
You absolutely need a thermal break between the bottom plate of the steel wall and the concrete. This is recommended by Building Science, and providing this thermal break will prevent thermal bridging from the slab and possible "ghosting" of the studs. Use XPS foam under the foam for a break.
You can glue sheetrock directly to XPS foam, but I wouldn't do it except for small spaces such as the back of a closet. Don't do it if you need to run wiring or plumbing in that wall.
After building the steel wall spaced slightly away from the XPS foam, I like to squirt some spray foam (but not too much) between the steel studs and the XPS foam. This will stiffen the steel wall and help prevent the XPS foam from coming unglued if there is a water problem or paint adhesion problem on your exterior wall (you said the wall is painted).
Read Andy Engel's article in FHB on finishing basements, and read the material available at http://www.buildingscience.com
Check out the photos below.
Billy
Edited 9/16/2007 9:12 pm ET by Billy
"After building the steel wall spaced slightly away from the XPS foam"Billy, what's the reason for the gap? Using XPS under the sole plate makes perfect sense. So, what did you then use to attach the sole plate to the concrete? Tapcons? Power Actuated Nails?Also, I noticed you were using cement board...were you tiling that or skim coating or?
The reason for the gap is that the exterior walls were not precisely plumb, and the XPS sheets did not lay completely flat. The small gap between the wall and the studs allows me to build a plumb wall without bumping into the XPS, and the space is useful for running wires behind the 1 5/8" studs. The studs have knockouts for wiring but you would hate for an errant sheetrock screw to pierce the wiring. This wouldn't be much of a problem in a 3 1/2" wall.
Use Tapcons to fasten the plate to the slab. Also, PL glue below and above the foam "plate."
The cement board was probably overkill, but I used it on the lower part of the wall just in case there was a basement flood event. Sometimes gutters clog, pipes burst, etc. Plus, part of the wall is behind cabinets and it would be difficult to replace wet sheetrock behind cabinets (assuming the cabinets are high enough off the floor to not get flooded.) Code requires the foam to be covered with 1/2" sheetrock or cement board, even if it is behind a cabinet.
Billy
Edited 9/16/2007 9:27 pm ET by Billy
Billy...do you then skim coat the cement board and paint, or are you applying something else?
Darrel,
In some places the cement board was skim coated with Durabond. In other places we installed wainscotting over the cement board.
Billy
Edited 9/17/2007 11:34 pm ET by Billy
The ideal product for your fireplace wall is the 1-1/2" Insulpink by Owens Corning. It comes in 2'x8' sheets already formed to accept 1x3" firring flush with the surface of the XPS.
I make my own 1x3's out of plywood (you can use treated ply if you wish).
Couple of things:
- You are correct that XPS allows water to pass, so it is incorrect to call it a vapor barrier. Use housewrap tape to seal between sheets.
- Densarmor will be a pain to skim coat (as others mentioned) National Gypsum makes a product called XP, and USG has a new Mold Tough drywall (looks just like the old greenboard) - both scored a perfect 10 on the mold growth test...and no skim coating needed.
- Dinosaur is right about the metal studs. They don't absorb any water, which seems an attractive idea. But the flip side is moisture will condense on them much easier than on wood because they have zero buffer capacity. And that equals liquid water. Bad news. Wood will absorb some moisture, but it will also dry out - that is the key to the Building Science method. If you insist on metal studs, wear gloves.
- Drywall shouldn't be glued to foam under any circumstances. You're going to regret it down the line. You really don't have an extra 3/4-in. of space to spare? furring strips of some kind would solve the problem nicely.
- You can mount a wood plate to the underside of a steel beam using the same ramset gun you plan to use on the floor. I've never done it, but I imagine it will be loud as all get out, and that the steel beam will probably rack your brain within your skull to ungodly levels of reverberation!
- I've got a similar project under way right now, did you see the basement thread in the "photo gallery" folder?
Justin Fink - FHB Editorial
"Everybody wants to know what I’m on...
What I'm on? I’m on my bike, busting my ### 6 hours a day…
...What are you on?"
- Lance Armstrong
Edited 9/17/2007 1:46 pm ET by JFink
"You are correct that XPS allows water to pass, so it is incorrect to call it a vapor barrier. Use housewrap tape to seal between sheets."XPS does not allow WATER to pass through it.Otherwise it my boat dock would be sitting on the bottom of the lake.It does allow a limited amount of vapor through. Don't remember the perm rating. But it is a retarder in the thicker verssions..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Thanks for the catch Bill - I know it doesn't allow water to pass, that was a slip of teh keyboard when I meant to say "water vapor".
It's so easy to get complacent with terminology on this stuff. Of course, that makes my correction of the incorrect use of "vapor barrier" even more ironic. sigh.
haha, thanks again. Justin Fink - FHB Editorial
"Everybody wants to know what I’m on...
What I'm on? I’m on my bike, busting my ### 6 hours a day…
...What are you on?"
- Lance Armstrong
If you insist on metal studs, wear gloves.
Sissy."Put your creed in your deed." Emerson
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
my mom thinks I'm tough! ;)Justin Fink - FHB Editorial
"Everybody wants to know what I’m on...
What I'm on? I’m on my bike, busting my ### 6 hours a day…
...What are you on?"
- Lance Armstrong
Ugh. Good point on the metal = condenser. Hmm...dang...why aren't these decisions ever simple? ;o)So, metal would be more 'flood proof' but the wood seems like a better solution for typical humidity in the basement. "You really don't have an extra 3/4-in. of space to spare? furring strips of some kind would solve the problem nicely."And how would one attach the furring strips to the foam?I like the insulpink product that was mentioned...that sure would save some time, but, at the same time...seems like a bit of a pain as I'd have to cut it all out to run wiring and add boxes and the like.
You going to have any HVAC down there? From what I've read the mold issue drops significantly if the RH is below 50%. IMHO you're going to have moisture in a basement regardless of what you do to prevent it, managing it is the key.
No HVAC. A gas fireplace insert (with fan) in the winter, and a dehumidifier in the summer.
Darrel,
Justin makes some good points. Using furring strips over the foam is better than gluing drywall directly to the foam (but you can do it if you need to). You can glue the furring strips (use treated wood) to the foam and attach them to the wall with Tapcons or other fasteners. Use studs if you have run wiring in the wall.
You are correct that metal is more flood proof than wood and it is also more mold proof. Plus you can built a rigid wall assembly with 1 5/8" 20 gauge steel studs, and you need 3 1/2" for a wood stud wall (or 2 1/2" for a crooked wood wall). I use steel in basements for these reasons, but wood can work fine.
If you insulate the steel wall assembly from the slab as I suggested, it will greatly reduce the possibility of condensation problems. Most of the condensation problems with steel studs in basements probably occur because the steel wall is built directly on the slab, resulting in studs that are at a lower temperature than the room in both winter and summer. If you sufficiently insulate the steel wall from the floor, the studs will be at the same temperature as the rest of the wall assembly and you're unlikely to get condensation on the steel. Remember, you need to use a dehumidifier in the basement as well.
Billy
Edited 9/17/2007 11:36 pm ET by Billy
Justin,
Building Science specifies steel studs as one of their accepted basement construction methods, as long as there is a thermal break. See Figure 12 in this Building Science publication by Joe Lstiburek:
http://www.buildingscience.com/documents/digests/bsd-103-understanding-basements/?topic=/systemsapproach/buildingenclosure/foundationassembly/main_topic
Billy