Mooney wall question

[bluedog225]

It will start cooling off in a month and I’m getting ready for being able to work out at the place.

I’m thinking of putting in a Mooney wall system over my existing framing to increase the R-value. Followed by netting and blown cellulose. The framing is pretty thick and some of these walls receive full Texas sun.

I’ve only got 1.5’ [edit 1.5”] for the finished surface before I hit the stair stringer.

Mooney wall is basically horizontal stringers to significantly reduce the thermal bridging from the studs to the interior. It’s more fully described here: https://www.builditsolar.com/Projects/Conservation/MooneyWall/MooneyWall.htm

My question is whether there would be any issues using 3/4“ thick furring strips? Either solid wood or plywood?

The “original” description of the wall uses 2x4’s cut in half. That is, 1.5” thick.

My plan is to run vertical nickel gap planks up the wall.

I was thinking 3/4“ thick strips every 16” on center. I’m also thinking 2“ or 3” wide would be fine.

What do you guys think?

Thanks

 

[Firebrick43]

Those studs look pretty close together and therefore the 3/4” furring strips won’t have a large span.

While you won’t get as much insulation due to the lower thickness you will still help minimize thermal bridging. And if space is a serious concern in that one area I don’t see the problem in doing so.

 

[Hank11]

I did the upstairs of my shop sorta like that...

I strapped the 2x6s of the attic trusses with 2x4s ripped in half, open cell spray foamed the full 7", trimmed the foam back to the strapping, and then drywalled it. It worked pretty well. It was easy too as I paid someone to foam it.

If you're looking for more insulation, I suggest you go thicker than 3/4". Ripping 2x4s is dead simple and you get twice the insulation room compared to 3/4" straps. Can't you just work around the stringer for the stairs? With 3/4" more insulation, I wonder if the slight increase in R value you might get will be worth the effort.

If the outside is not complete, I'd think about more insulation out there.

 

[racecougar]

I think the OP meant 1.5" of clearance to the stair stringer instead of 1.5', as that would explain the desire to go to 3/4" furring strips instead of ripped 2x4's.

 

[billconner]

I wonder if the slight increase in R value you might get will be worth the effort.

The strapping even without insulation would be worth it because of the reduced conductive loss through the studs. Thermal bridging.

 

[bluedog225]

Yes. 1.5”. Sorry.

My understanding is that the thermal bridging reduction is the big advantage of the system.

Outside is finished. Metal-3/4 mylar polyiso-1x4 pressure treated stringers-tyvek-3/4 ply.

 

[firebirdparts]

I'd do it. You have a ton of meat in that wall, the most I've ever seen in a wall.

I never did blow in cellulose in a vertical wall, but I can see where that's a ton of work in this case.