Cantilever insulating

[cableman]

Im redoing my porch and now have access to insulate the floor of my upstairs that hangs over.

If i pull the insulation thats there now i can see right in to the inside ceiling.

Should i block that off and air seal each bay then fill with roxel? Or should i just cover entire area in 2" tuff r dow board and seal all the seams?

 

[vinny11950]

I would stuff a few inches of Roxul in each bay, make it tight, mostly to keep insects away. Then the foam boards with sealed edges (either spray foam or weatherized foil tape). Then I would try to cover the whole thing with a wire fence material (preferably with small holes and rust resistant) to make sure no squirrel ever gets in there.

 

[cableman]

I figured if i didnt seal this area off from the inside ceiling, what ever heat transfers through ceiling sheetrock would actually keep it warmer and less likely have a heat pipe freeze.
I would however seal the bottom and front with the dow board and great stuff all seams and against house.
Once porch ceiling is covered it shouldnt have any way for critters to get in so im not too worried about covering with mesh.

 

[cableman]

Pulled a little more crap down. Im gonna stuff roxel in each bay and cover this entire area in 1/2" tuff-r dow board sealing it against the house and any seam.
Is roxel r23 enough for this area or should i stuff 2 layers of r15? The joists are 7" deep, guess they shrunk quite a bit! Was prolly 7-1/4 when built.

 

[vinny11950]

Sounds like a good plan. Just make sure the insulation travels into the bays into the living area a few inches to give you more insulation. Air sealing is very important then as you don't want this to be a place to lose heat, air conditioning or letting moist air in or out. Unless you think the house design needs it. But it looks like the builder just overlooked this section.

I would do the Roxul R23 and cut additional strips of 1.5 inches to fill the gap. Make sure it is nice and tight. You could do the same with Fiberglass, but it is trickier to do as you don't want to compress the fiberglass too much.

 

[Swedishchef]

Haha..Good idea.

But I was going to suggest spray foam the entire damn thing.

Roxul has gone up significantly in price in the past 7 years here.

Andrew

 

[cableman]

How would i cut the 1.5" strips? This is why i maybe thought 2 layers of r15 would be a perfect fit. I can also get 2 pieces put of one batt as this section is 22" deep. I think 2 packs of the r15 covers it, something around 24 bays i counted in the dark last night.

 

[vinny11950]

I was thinking Roxul R23 is 5.5 thick so you could cut 1.5 inch thick pieces on the flat side to get to 7 inches or so. Maybe 1.75 to give you a little compression top and bottom. Roxul is easy to cut with a bread knife. But I also like the new fiberglass products they have, so go with that if you like it better. Either one will do.

I am sure you are fine, but inspect inside the bays as you go along looking for any surprises like water damage, mold or anything else you might want to address before you close it up.

 

[cableman]

I just figured it was easier cutting the r15 roxel in half and using both in one bay getting r30 out of it plus that would fill the depth of the joist. Either way i guess

 

[cableman]

Used 2 bags of roxel r15, cut each batt in half and used the 2 halfs in each bay. Topped it off with 3/4" dow board and sealed with great stuff pro. Should work well i hope!

 

[vinny11950]

Really nice work. A bag of Roxul around here is $50, so altogether you probably spent $150 in supplies to save money in the long run. Smart choice.

Congrats.

 

[cableman]

Really nice work. A bag of Roxul around here is $50, so altogether you probably spent $150 in supplies to save money in the long run. Smart choice.

Congrats.

$174 with tax, can of great stuff pro too and some nails and screws. Well worth it, this section is 23"s deep into my master bed/bath and front bedroom, master bath floor was really cold last winter. Im surprised the shower drain or heat pipes didnt freeze the way this was originally done.
Ill have to finish up the soffit and move on to the back cantilever.
Work is never done!

 

[cableman]

Ripped a section of the back cantilever, unreal how crap was insulated back then. Great stuffed 2" dow board on top plate and Ill finish this off with roxel also.

 

[vinny11950]

Wow, good thing you found and insulated that pipe.

Good job, again.

 

[Lake Girl]

Ripped a section of the back cantilever, unreal how crap was insulated back then. Great stuffed 2" dow board on top plate and Ill finish this off with roxel also.

Sad but have seen it before ... unless you are onsite watching the build or doing it yourself, short cuts can happen. Not every contractor is diligent in getting quality help.

The insulating you are doing should make a big difference in comfort and prevent potential freeze disasters.