Home>Discussions>INSULATION & HVAC>isulating walls with no studs
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Sombreuil_mongrel
Re: isulating walls with no studs

The reason people stud in the box walls is as much to improve the actual structure (the vertical planks carry the roof load _only through_ the nails which fasten them to the sills) as to gain insulation. The box construction was very quick and cheap to erect, at considerable cost to the permanence of the building and safety of its occupants. I'm amazed that many remain as do. They literally baffle engineers, because box houses fly in the face of every rule of structure.
Casey

JLMCDANIEL
Re: isulating walls with no studs

Do you have large beams at the corners? It may be post and beam construction. Perhaps even and old barn that was converted.

Jack

robere
Re: isulating walls with no studs

Dont know about the beams on the corners. All I know is it's solid walls. No air space

Fencepost
Re: isulating walls with no studs

If the wall is structurally sound (and that's a subjective judgment I can't make here), then I see no particular reason to fur it out. Were it up to me, I might just completely cover the interior of the wall with foam board, then drywall over the top of that, using screws long enough to go through the foam board into the wood.

As for the structure, the existing boards may be sufficient to support the vertical load. They may not, however, be sufficient to prevent racking (shear). The foam board, if glued and fastened to the boards, and the drywall with sufficient fasteners properly installed, *may* provide good shear strength. (Only a structural engineer is qualified to advise you on this.)

robere
Re: isulating walls with no studs
Fencepost wrote:

If the wall is structurally sound (and that's a subjective judgment I can't make here), then I see no particular reason to fur it out. Were it up to me, I might just completely cover the interior of the wall with foam board, then drywall over the top of that, using screws long enough to go through the foam board into the wood.

As for the structure, the existing boards may be sufficient to support the vertical load. They may not, however, be sufficient to prevent racking (shear). The foam board, if glued and fastened to the boards, and the drywall with sufficient fasteners properly installed, *may* provide good shear strength. (Only a structural engineer is qualified to advise you on this.)

Hhhmmm. Sounds like the easiest ( and cheapest ) way to go. Didnt know if I could do this or not. My main concern was doing something that would cause the wall to sweat.
The walls have been holding up for 80 years with no bowing or anything. I understand what you're saying about supporting the sheetrock. Guess that would be somewhat of a gamble on my part.

canuk
Re: isulating walls with no studs
robere wrote:

Hhhmmm. Sounds like the easiest ( and cheapest ) way to go. Didnt know if I could do this or not. My main concern was doing something that would cause the wall to sweat.
The walls have been holding up for 80 years with no bowing or anything. I understand what you're saying about supporting the sheetrock. Guess that would be somewhat of a gamble on my part.

I've only read about the type of structure you have .

The only reason you should have any concerns for *causing the walls to sweat* would be if you had warm moist air from the inside contacting the cold exterior wall surface. If you properly attach the rigid foam to the exterior wall surface and completely seal all the corners , ceiling , floor , butt seams there shouldn't be a concern.

northforkhippy
Re: isulating walls with no studs

I live in a "box-built" house in southwest Virginia that was originally wall-papered with pages from a 1918 newspaper. Although it lists a little to the south and the east (away from prevailing winds) the structure is still sound. I enlarged an existing window opening to install a double window and nailed a rough-sawn 1x to the planks to serve as header 9 years ago with no problems observed. Structurally, a typical house built with 2x4/6 studs every 16 inches is over-engineered. A 2x4 every 8 feet could adequately support many of the vertical loads imposed on a structure. The 80 year longevity of your home speaks for itself.

A neighbour of mine (now deceased) studded the interior of his box-built home years ago, and updated the wiring and insulation to the standards of the time. It's fairly straightforward to fur the window jambs out to match the new thickness. I have used rigid foam in the upstairs end-walls of my 1 1/2 story house and observed no evidence of sweating. When time and money permit I will not hesitate to do the same in the rest of the house. Even if you stud the walls out for insulation and wiring upgrades (I ran wires in a custom baseboard) you can use still use panelling instead of fooling with drywall, just account for the thickness of the wall finish when extending the jambs of your doors and windows.

robere
Re: isulating walls with no studs
northforkhippy wrote:

I live in a "box-built" house in southwest Virginia that was originally wall-papered with pages from a 1918 newspaper. Although it lists a little to the south and the east (away from prevailing winds) the structure is still sound. I enlarged an existing window opening to install a double window and nailed a rough-sawn 1x to the planks to serve as header 9 years ago with no problems observed. Structurally, a typical house built with 2x4/6 studs every 16 inches is over-engineered. A 2x4 every 8 feet could adequately support many of the vertical loads imposed on a structure. The 80 year longevity of your home speaks for itself.

A neighbour of mine (now deceased) studded the interior of his box-built home years ago, and updated the wiring and insulation to the standards of the time. It's fairly straightforward to fur the window jambs out to match the new thickness. I have used rigid foam in the upstairs end-walls of my 1 1/2 story house and observed no evidence of sweating. When time and money permit I will not hesitate to do the same in the rest of the house. Even if you stud the walls out for insulation and wiring upgrades (I ran wires in a custom baseboard) you can use still use panelling instead of fooling with drywall, just account for the thickness of the wall finish when extending the jambs of your doors and windows.

Cool. My wiring is updated but I'd still have to re-run the outlets that are in the window casings. When you did your foam board, did you fir strip it out? What kind of foam board did you use?

northforkhippy
Re: isulating walls with no studs

Pardon the delay in replying, I haven't been on the 'net much lately. I installed the foam directly to the boards with no air space (the space may provide a space for moisture to condense). I did install horizontal nailers to attach the wall finish, in this case 1/4 panelling. The foam board I used was salvaged from left-over scraps from a flat-roof project in the area. I believe it is a polyisocyanurate type, a closed-cell foamed plastic insulating core that is sandwiched between organic or inorganic felt facer. It has a thermal resistance of about 6.00/inch.

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