Interior wall replacement question

[RollinRox]

Hi all,

I ripped down the plaster and lathe original wall in a bedroom in my row home. The wall is an outside block/brick wall. So it was plaster and lathe on firring strips that were nailed directly into the block and brick, with no insulation. I am wondering if I should just attach new studs to wall and then drywall, or if I should add any vapor barrier, or dry lok, and/or insulation.

Anyone have any input/experience in doing this and care to share?

[StrangeTanks]

You can put up a plastic vapor barrier. The frame it out. You don't have to attach the studs to the brick, just frame from floor to ceiling. I usually like to frame it up with 2x3's. This gives you the opportunity to correct the interior wall to make it plumb and straight. You also have the opportunity to put in some extra outlets or phone and cable lines. I would go ahead and insulate with fiberglass batting.

Pay special attention to how you will be trimming out the windows and make your openings accordingly. Thats usually where you run into problems later. The opening is either too large or too small to allow you to install trim properly or there's nothing to attach it to on the window side. Also make ignore plum and level on the window openings, windows are probably all wacked out after 100 years, make the framing match the existing opening unless your planning on framing out the entire window opening all the way to the outside.

[RollinRox]

Thanks Strange! That's a great idea about offsetting the new framing. Keeps things simple. I was already planning to use 2x3s, but tapconned to the block, and trying to squeeze new outlets in. Keeping the new wall an inch of so off the block will definatley do it. It's an exterior wall, but on an alleyway between us and the next house, so no windows.

[rjj]

You can put up a plastic vapor barrier. The frame it out. You don't have to attach the studs to the brick, just frame from floor to ceiling. I usually like to frame it up with 2x3's. This gives you the opportunity to correct the interior wall to make it plumb and straight. You also have the opportunity to put in some extra outlets or phone and cable lines. I would go ahead and insulate with fiberglass batting.

Pay special attention to how you will be trimming out the windows and make your openings accordingly. Thats usually where you run into problems later. The opening is either too large or too small to allow you to install trim properly or there's nothing to attach it to on the window side. Also make ignore plum and level on the window openings, windows are probably all wacked out after 100 years, make the framing match the existing opening unless your planning on framing out the entire window opening all the way to the outside.

no need to attach the studs to the brick? What if you dont have access to the joists on the floor above? tight shims will do?

[RollinRox]

I have 2x3 framing for the ceiling (there's some empty space between ceiling and rafters) that I can attach the top of the new wall frame to.

[StrangeTanks]

no need to attach the studs to the brick? What if you dont have access to the joists on the floor above? tight shims will do?

You put blocking between the joists to attach the top of the new wall to. If you don't want to disturb the existing ceiling then I would attach a board at the top of the brick wall that you nail your framing to.

[ericlowry]

You can put up a plastic vapor barrier.

DO NOT put a plastic vapor barrier on the outside of any exterior wall. During the winter, moisture from inside will condense on that plastic inside the wall and you will guarantee moisture and mold inside the wall.

You should definitely insulate. There are multiple methods to do this including fiberglass batts, rigid board, and spray foam.

I would be happy to answer more questions.

Thanks.

Eric

[RollinRox]

Thanks Eric,

Do you mean on the inside of the brick wall (warm side in winter)?

[ericlowry]

Correct. In this climate, if you put a vapor barrier at all, it should be located immediately against the back side of the sheetrock. However, unless your wall is VERY well insulated and air sealed, you will get some moisture in the wall which may condense on the vapor barrier. This can be done, but typical construction practices do not air seal and insulate well enough to eliminate this condensation.

Thanks.

Eric

[sharkey]

If you want to save an inch, frame the 2x3s sideways and put 1 1/2' foamboard in between studs. If the brick wall if pretty straight, instead of framing you can glue and nail furring strips to it and insulate with 3/4" foamboard in between. With furring strips remember to use the short 1 1/4" drywall screws to put up the drywall.

[ericlowry]

For an exterior wall, you will want at least R-13 insulation. This is 3 inches of rigid foam board insulation or 5.5 inches of fiberglass. You could also use 2 inches of polyiso rigid insulation.

Don't skimp on the insulation and air sealing. You have the wall open, so make it right now.

Thanks.

[NJbound]

know whats nuts? Everyone *thinks* the old homes were built so good too. It was the same way in out old row home to with old newspaper stuffed in some holes for insulation. Crazy. No insulation.. wow.

[HomeInspectorBC]

Hello and Happy Sunday,

Another idea is to use a breathable sealant on the masonry wall if moisture is an issue, using a plastic vapor barrier is conducive to trapping moisture within the building envelope along with all the indoor air quality issues that come with excessive moisture, if you are sold on this approach it is worth looking into installing housewrap on the exterior side of the wall framing which is a breathable product designed to keep vapor out while allowing the building to breathe.

As far as framing out the walls studs sideways, this leaves the wall prone to bowing/moving overtime as well as prevents a good amount of insulation from being used. Using 2 x 3's sideways or not for wall studs reduces the amount of insulation one can use so a decision will have to be made regarding gaining extra living space versus reduced energy bills/indoor comfort levels. 2 x 6's is one option for the extra insulation(R-19) but they are not always approbriate due to budgeting and reduction in living space area; 2 x 4's is another option if the size of living space is a concern to allow for a minimum of R-13 batted insulation. Spray on insulation might be another option worth looking into but would most likely require professional installation and add cost to your project.

Speaking of insulation approximately 90 percent of heat transfer is stopped in the first 6 inches of insulation which is why 2 x 6 wall studs are sometimes installed as they allow R19 fiberglass batted insulation to be used; R-13 = 3.5 inches of fiberglass batted insulation and is the most common but is too thick to use with 2 x 3 wall studs as R-11 is typicaly used with 2 x 3 wall studs which is only 3 inches thick. As far as foam board insulation and R values: Expanded Polystrene foam board has a typicall R value of 3.6 - 4 per inch, Extruded Polystrene foam board insulation R value is 4.5 - 5 per inch and the more expensive stuff Polyisocyanurate & Polyurethene has a typical R value of 7 - 8 per inch but is known to off gas creating indoor air qualitiy concerns as well as loses R value as it off gases.

Hope this is some food for thought as you go about making your home a nicer and more energy efficient place to live and enjoy for years to come,

[StrangeTanks]

know whats nuts? Everyone *thinks* the old homes were built so good too. It was the same way in out old row home to with old newspaper stuffed in some holes for insulation. Crazy. No insulation.. wow.

Lets see how brand new mcmansions fair in 150 years...

[sharkey]

FYI If you want to put 6" of insulation in the wall, you DO NOT have to frame with 2X6's. Frame with 2X3's and frame 3" away from the wall.

[HomeInspectorBC]

Using 2 x 3's for wall framing three inches away from the exterior wall leaves too many voids behind the finish wall which reduces the R-value of the 6 inch insulation, the energy efficiency/indoor comfort levels as well as defeats the purpose of using 6 inches of insulation. In most cases it is a good practice to frame as tight to the exterior wall as possible to help prevent voids and to use a fire rated foam insulation between openings in the framing made for wiring as well as outlets/switches and other penetrations in the walls to help prevent drafts and for improved fire safety.