Moisture Barrier for Partially Below Grade Grouted CMU Wall

sequoia_2007

14 years ago

We gutted our kitchen as part of a repair to our foundation. While removing the drywall from the wall separating the kitchen from the garage we discovered the sole plate for the wall rested 24Ã¢ÂÂ above the floor and the drywall was not fastened to the grouted CMU wall. We asked the contractor who rebuilt our floor to use a moisture barrier between the plywood and the grouted CMU wall and he left us the rest of the roll. The moisture barrier is the black sheet material rising from the floor in the photo above.

The soil under the garage slab starts about 12Ã¢ÂÂ below the sole plate. We thought we would add another section of the moisture barrier from the sole plate down to the floor. Does the moisture barrier need to overlap the layer of moisture barrier below and by how much? Next we would fur out the wall with 1x4. Do the furring strips need to be pressure treated? Finally we would cover with 5/8Ã¢ÂÂ moisture resistant, fire code drywall.

Is this the best code compliant approach under the 2006 International Building Code?

Thank you for taking the time to read my post and consider my questions.

Howard

Sort by:Oldest

Comments (4)

manhattan42
14 years ago
5/8" fire rated drywall is not required under the 2006 IRC. Only standard 1/2" drywall is required between the garage and habitable interior space.

The moisture barrier should also not be required on the interior side of the CMUs provide they had been dampproofed or water proofed on the garage/soil side.

2006 IRC requires any lumber that comes into contact with masonry walls below grade to be preservatively treated.
This means your furring strips would need to be presevatively treated.
sequoia_2007
Original Author
14 years ago
Thank you for taking the time to respond.

Since we have to use 5/8Ã¢ÂÂ fire code rated drywall on the wall to the right we decided to use it on all the kitchen walls.

Based on the original drawing for our home there is a moisture barrier shown below grade on the garage side of the CMU wall. It appears to be intact since we get heavy effloresce on the surface of the garage slab, but the interior side of the wall does not show effloresce. Also, when we removed the kitchen drywall that was in contact with the CMU wall there was no sign of moisture.

Regarding the use of pressure treated furring strips. It sounds like we only need them if a moisture barrier is not provided. If a moisture barrier is provided then we can use untreated lumber?

Howard
0
Related Discussions
diy poured wall - diyers only
Q
Comments (30)
There is not anything actually pushing on the wall. It's simply a verticle concrete wall built between a house and a hillside (but not in a hillside) to serperate the sitting area from the parking area and tied into a patio which will more than likely be dressed up (with stucco?) and further aid in a little water irrigation. I was wanting the height so it'd be able to sit on the patio and not see the cars on the other side but with a little more dozer work on my part I think I can lower the parking area to help lower the wall like people have suggested. As far as architects or concrete contractors go, there are no architects and the closest advertised concrete contractor I can find on google is somewhere close to 100 or so miles away. Unless you mean Day laborers that call themselves contractors or Commercial Contractors that build Highways and Walmart supercenters. I've tried calling these guys about small stuff like my pet project and they are never (ever) interested and for good reason I suppose. There are no Building requirements around here and to be honest that probably let people just started building themselves. It is probably the entire reason there are very few contractors and then that caused the need for community construction, where the community congregrates and 'Barn Raises' as the need arises. Above sarcasms aside It was done this way long before any engineering schools and will probably go on for some time to come, either out of need or sport. However I also fully understand peoples' need to defend their professions and if I had went to school and spent my life dedicating myself to said profession I wouldn't want a country full of DIY idiots thinking they could do it themselves either. But what are you gonna do. It is what it is. This type of construction goes way beyond concrete and I think some people don't realize that in unregulated areas people can still build an entire house or anything else (for that matter) for materials only if they want to take the time learning a DIY solution. We all have gardens, patios, front porches, driveways and houses even when we have to (or want to) build them ourselves. Of course I appologize for the bickering the post caused. I had hoped if I actually labeled the thread "DIYers only" Everyone wouldn't have to endure a 'Professional VS DIY' thread. That having been said I'm looking forward to building my new wall in the spring and look forward to reading everyone's comments on the subject. That is if the thread hasn't been ruined yet. Thanks guys. I hope everyone has a nice weekend.
...See More
Delta FL or other membrane on basement walls?
Q
Comments (3)
Forget the dimpled membrane on the wall. As you read, it is for use in conjunction with an interior French Drain where you have active liquid water penetration. (Leave aside that this is a problematic form of waterproofing in the first place.) The idea of leaving a gap between the insulation and the wall--so it can "breathe", no doubt--is one of those old ideas handed down from father to son with no basis in building science. Whether you use spray foam or foam board, it should be directly against the wall. All forms are permeable and water vapour will find its way through without damaging the insulation. If you have an active liquid water leak, of course, the foam will not stop it. By leaving a gap you risk letting the wall going below the temperature of the basement and, depending on the relative humidity of the air, hitting the dew point, thus becoming liquid water feeding mould growth. will frame out a 5 X 10 boiler room in the corner of the basement that I will not be installing the wall membrane or a floor system to. Is this good or bad? The floor membrane is to protect the flooring. If you leave the concrete bare, no problem. Ditto with the walls. But even if it's too difficult to install a finished wall and insulation, sealing between the sill and foundation with polyurethane foam/caulk will cut down energy robbing air infiltration. Here is a link that might be useful: Basement Insulation Systems
...See More
Insulation and no vapor barrier questions... help
Q
Comments (19)
It depends on where you are located. I have always lived in Canada and the codes call for foundations and footings for buildings, decks and fence posts to be 4 feet below ground, because of frost penetration and heave. This extreme cold transmits through concrete walls. You can feel the cold on the walls and if the basement is not heated, frost will actually form on the surface. This is a fact, as I had a house with no central heat in the basement once. As well as possibly creating damaging condensation within finished walls, without insulation and vapour barrier, it can result in mold. It will also increase the cost of heating the overall house. I am a retired architect and have renovated several of my own houses which were handy men projects, so have gone through the whole gamut many times.
...See More
Curbless shower on below grade slab
Q
Comments (9)
First..do a moisture test on your existing slab. You want to see if moisture vapor is coming up into the basement from under the slab. Tape a 2' square sheet of poly on the floor and see if there is any moisture under it after 48 hours. If the moisture is significant, it might play into what type of membrane you use on the floor. Memebranes like Hydroban and Kerdi have similar properties when it comes to liquid moisture, yet differing properties when it comes to moisture vapor transmission. Significant moisture drive could actually lift and delaminate a topical membrane from the slab. If you have under-slab drainage or radon ventilation pipes, and foundation perimeter footing drains, you should be in fine shape. I'd make it a wet room, pretty much follow Bill's advice; -slope the entire floor to the drain. -topical membrane on the entire floor and up about 6" on all the walls, or just fully membrane all the walls. Fully membrane the shower walls. -ventilation. Don't skimp. This room will be cool and the basement itself is typically humid, so latent drying action will be less than in an upstairs bathroom. Do what you can to eliminate moisture vapor as it is generated. -I'd not insulate or heat the floor. You might have to balance relative humidity in the basement as a whole with a heat source in the bathroom. If you do have vapor drive into your basement, it might help to have something as simple as an IR bulb on a timer to help with the initial drying of the room. For a humid, slow-to-dry shower environment; A non-porous porcelain tile might be better than a porous natural stone tile. An epoxy type of grout might be better than a portland-based grout.
...See More
manhattan42
14 years ago
"Regarding the use of pressure treated furring strips. It sounds like we only need them if a moisture barrier is not provided. If a moisture barrier is provided then we can use untreated lumber?"

Yes.

Only when lumber is in 'direct contact' with masonry walls below is preservatively treated lumber required.

As long as you place the impermeable 'moisture barrier' between the furring strips and CMUs, no treated lumber furring strips are required.

However, if this 'moisture barrier' will also be a 'vapor barrier', it will be located on the wrong side of the wall assembly and could cause unwanted condensation problems.
(A 'vapor barrier' should be install on the warm-in-winter side of a wall assembly immediately under the drywall and immediately over the studs or furring strips.)

It is likley a better "code compliant" installation to simply use treated furring strips and no mositure barrier at all.

But for such a small area, should not matter much either way you choose to do it.
0
sequoia_2007
Original Author
14 years ago
Sounds like our best approach is to use pressure treated 1x4 furring strips running from ceiling to floor. We will use insulation in the stud bay above with the vapor barrier facing the drywall. No insulation between the drywall and CMU wall. Do you recommend any type of coating for the interior side of the CMU wall before we attach the furring strips?

Thanks,

Howard
0

Moisture Barrier for Partially Below Grade Grouted CMU Wall

Comments (4)

manhattan42

sequoia_2007
Original Author

Related Discussions

manhattan42

sequoia_2007
Original Author

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

Moisture Barrier for Partially Below Grade Grouted CMU Wall

Comments (4)

manhattan42

sequoia_2007Original Author

Related Discussions

manhattan42

sequoia_2007Original Author

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

sequoia_2007
Original Author

sequoia_2007
Original Author