Insulating 2''x3'' walls

[flyguy]

We have an old house which is getting rewired, so I've pulled all of the drywall off from the walls and ceiling.

The walls are 2x3 studs and were not insulated.

Does it make sense to "furr-out" the 85 or so external wall studs to get 2x4's so that the wall insulation doesn't need to be compressed/modified to fit in the shallower wall cavities?

Thanks!

-- Mitch

[HayZee518]

it might be better to have insulation urethane foamed in place. 2x3 studs are really never used for construction. they warp and bend and do not have the load bearing capacities that 2x4 or 2x6 have.

[flyguy]

"2x3 studs are really never used for construction. they warp and bend and do not have the load bearing capacities that 2x4 or 2x6 have."

I'm sure that's why they're no longer used in construction today.

This home, along with all the others on the street were built for workers at a nearby cellophane factory - brick exterior and hardwood floors, but cheaply built otherwise.

As the house is now 50 years old and shows no signs of collapsing, I'd like to try to keep the occupants warm.

How does spray-on insulation compare to fiberglass, cost-wise? We're trying to be economical and get the most warmth for the money.

[mark121268]

furr out

i have thought of this , bit of a hassle but i got nothing but time, think i am leaning towards that . some pl premium and a couple brads. just my thought tho

[mark121268]

as for the spray foam

my mobile home is 60x12 had a guy come in and give me the cost of doing it for all walls and underneath of trailer 5 grand, think will furr out studs and insulate with roxul

[HayZee518]

the 2X3's are installed sideways so the mean thickness is 1 5/8" and it isn't a full 2X3. 3/4 inch furring will decrease your overall room size plus the thickness of your drywall. foam boards may work, but you still have to foam gaps.

[pushkins]

IMO having someone spray foam the walls would probably be your best option, it may...no will, cost more but you don't lose any room size, end up with a far better insulated envelope. At best with fiber insulation on 2x3 studs you'll end up with R6-10, same size spray foam R15 min.

[mrcaptainbob]

2x3 studs...

Not to mention the rigidity added to those meager studs by using the spray foam.

[manhattan42]

Oh yeah.

'Structural foam' insulation....

------------
Forget the foam. It will NEVER pay for itself.

Use whatever fiberglass, rockwool, cotton or cellulose you can fit into the cavities then do you best to limit air infiltration.

You will achieve more in energy savings with the least cost.

Foam will be a complete waste of money.

[pushkins]

Oh yeah.

'Structural foam' insulation....



I don't believe anyone made any mention or suggestion of "structural" enhancement.

[mrcaptainbob]

Structural foam....

Well, check out foam core.....putting a membrane or other covering (read 2x3's...) either side of, and in intimate contact with, foam will provide a remarkably strong product. Stronger than either on it's own. Not to mention the intimate contact with the outside wall. That would totally insulate, fill/plug all air gaps AND provide a sound structural contribution to those 2x3's. Try an experiment....fill a small cardboard box with that expanding foam. Leave the top open to allow it to do it's expanding. After it sets up....see if you can crush it by driving your car over it....the cost is the price of less than a half a can of that stuff....

[manhattan42]

Oh yeah.

'Structural foam' insulation....



I don't believe anyone made any mention or suggestion of "structural" enhancement.

Sure they did.
mrcaptainbob stated:

"
Not to mention the rigidity added to those meager studs by using the spray foam."

The shear wall/structural reinforcement aspect of adding the foam will be next to nil...Which is why let-in bracing is required even when foam boards are used over 2x4 or even 2x6 studs.

[Mark in Vancouver]

Spray Foam is exactly what you need

Spray foam insulation was made for narrow wall cavities. At R6 per inch of depth, you can create an genuine thermal envelope in your 2x3 walls whereas anything else, you will be left with lab tested R6 - and real world performance below that.

2Lb foam increases structural rigidity and will add to the useful lifespan of your home.

It is more costly, but ONLY if you are looking t the up front expense. If you use energy to heat or cool your home at all, you will find the payback period a reasonably short 5 years.

Look for a good spray foam insulator in your area or check out 'ecologicfoam' on youtube to see what is involved.