Spray foam question ~ kinda

[Cobra4706]

Hi all, I have a garage that is vinyl sided and has a finished interior. During some electrical work I found that it had R9 insulation. There are several companies that do ‘retro foam” where they pull some siding and spray foam in the wall cavity. Theoretically, it makes sense to me, does none hve any experience with this? Pros? Cons?

Thanks!

 

[930dreamer]

Are talking about removing interior sheeting or exterior siding, all the cavities have to be done.

 

[Cobra4706]

Are talking about removing interior sheeting or exterior siding, all the cavities have to be done.

They pull the siding off about mid wall and drill through the outside between each set of studs and blow the foam in.

 

[930dreamer]

They pull the siding off about mid wall and drill through the outside between each set of studs and blow the foam in.

If I was going to pay the spray foam rate I'd want to see that every inch of the cavity got filled, no way to verify that from a drill hole but I'm a functioning idiot.

Like this?

 

[Cobra4706]

If I was going to pay the spray foam rate I'd want to see that every inch of the cavity got filled, no way to verify that from a drill hole but I'm a functioning idiot.

Like this?

That is it exactly.

 

[P0sTaL]

I know someone who had that done and the wall cavity didnt get fully covered. He ripped one of the section to check. Personally if the budget is there than rip it all down inside and do it right anf reduce the unknown questions in your head.

 

[kj_mustang]

Looks like they are pumping in open cell foam. You are not going to get a very thick layer of foam with the existing insulation in the wall. You better have a good understanding of water vapor transmission through the wall for your type of construction and the humidity levels of your local climate. That thickness of foam will not be a water vapor barrier and will probably hold water in the right conditions.

 

[56Mark]

Unless you are doing it just to make it more comfortable to work in, I don't think you will ever get financial payback on this project. I would take the interior down and spray it all, but that is a lot of work and cost. Might be worth it if you are in the garage a lot and going to live there for a long time.

I spray foamed a new house 2 years ago with mostly open cell, about 2,100 sq ft heated on main level and 700 in the basement and all electric appliances, 16 SEER heat pump in east TN and the year around electric bill is about $110/mo average ($70 low spring/fall, $180 high in winter) paying around 11 cents per KWH. I would do it again.

 

[karoc]

Just to expensive to go at it kinda blind

 

[Cobra4706]

Thanks for the input!