DIY Home Improvement Forum banner

1 - 12 of 12 Posts

·
Registered
Joined
·
95 Posts
Discussion Starter #1
The hatch to my condo's attic is merely a slab of sheetrock/wallboard cut to fit the opening. Considering the rest of the attic has about 6" of unfaced fiberglass rolled between the joists, I'm guessing I'm losing/gaining some heat via this hatch.

I'm thinking of cutting a sheet of plywood to the right dimension, and fastening some rigid foam insulation to the attic side. Since I'd have to buy the insulation in large pieces, I thought I could perhaps put two (or more, as practical) layers to increase the R-value.

My main question is how to fasten the foam insulation to the plywood and to itself, if I layer it. Is construction adhesive OK? I don't want to use the wrong adhesive and end up damaging the insulation.

Any thoughts, tips, or alternatives welcome!

Larry
 

·
Registered
Joined
·
37,139 Posts
That will work.
Look right on the tube, it will say what not and what to use it for.
 

·
Registered
Joined
·
1,978 Posts
I suspect for fire rating you would still have to start with the piece of sheetrock. Code experts here can confirm.

When you shop for construction adhesive, look for the words 'foam-safe'.
 

·
Registered
Joined
·
11,194 Posts
Six inches of attic insulation in NJ is a little light. Try adding another 6 inches. For the attic hatch, just put a few dabs of silicone caulk on the sheetrock and put the foam on that.
 

·
Banned
Joined
·
17,158 Posts
I suspect for fire rating you would still have to start with the piece of sheetrock. Code experts here can confirm.

When you shop for construction adhesive, look for the words 'foam-safe'.
He already does. He has to attach it to the Plywood, so that the Foam board can be placed on it. The plywood will help keep the drywall from buckling over time.

My scuttle actually is just a piece of plywood, with a box frame around the inside perimeter and then some unfaced Batt Insulation for a R-30 on it.

Even going the extra mile with mine and sealing with some clear Silcone Caulk, helps to stop any drafting, if there is a small gap where it sits down on the molding that was put in to keep it from dropping out of place when closed.
 

·
Registered
Joined
·
95 Posts
Discussion Starter #9
Thanks for all the tips and suggestions.

Sheetrock: :vs_bulb: Ok, I'll get another piece to cover the plywood (the existing piece is missing a corner)

Insulation: I well know 6" is light on insulation! :surprise: My place (built in 1986/7) can cool off/heat up far more rapidly than I think it should. What I have now is just the unfaced FG between the joists. I want to add more crosswise to 12-18" depth, at least over the half of it I can do that, which includes the bedroom. The other half is a cathedral ceiling that goes from 12' to 8' over about 25', and there's really no way to improve that insulation short of ripping down the ceiling, or perhaps blowing in FG. Fortunately, there is a large space over the cathedral ceiling, at least at the tall end (the roof line and the ceiling line are intersecting lines, not parallel) . The other big issue with heating/cooling is all my ductwork is in the unconditioned attic space, and that is under-insulated as well... It's lovely getting a blast of cold air the first few minutes on those winter mornings... :glare:

I also need to straighten out my bathroom venting situation. Thinking about a central system to pull from both bathrooms...

So, it'll be:

Attic
-----
Foam insulation
Foam insulation
Plywood
Sheetrock
-----
Living area

with glue in between the layers.

Again, thanks to all!
 

·
Banned
Joined
·
17,158 Posts
For the Bathrooms, I would do a central exhaust unit that will allow the Bathroom Fart Fans to not wake up everyone in the building. You basically have a light and/or box with a duct that goes back to the remote fan. It has a damper to only pull from the bath in use.

Keep in mind that some places, they have the bath fan on a trigger to start a fan to pull in fresh air, if the place is outside environment tight.
 

·
Registered
Joined
·
95 Posts
Discussion Starter #11
For the Bathrooms, I would do a central exhaust unit that will allow the Bathroom Fart Fans to not wake up everyone in the building. You basically have a light and/or box with a duct that goes back to the remote fan. It has a damper to only pull from the bath in use.

Keep in mind that some places, they have the bath fan on a trigger to start a fan to pull in fresh air, if the place is outside environment tight.
Thanks. That's just what I'm looking to do. I don't think my place is that air tight, but it might help some to have a make-up air fan. Especially since the bathrooms (one is mostly laundry with a sink & toilet) have no windows to the outside.
 

·
Banned
Joined
·
17,158 Posts
Thanks. That's just what I'm looking to do. I don't think my place is that air tight, but it might help some to have a make-up air fan. Especially since the bathrooms (one is mostly laundry with a sink & toilet) have no windows to the outside.
You will never find any place 100% air tight. Those that are really air tight, you have to bring outside air to allow the house to breathe.

My house is over 75 years old. I have gone around and sealed just about every leak that I could find. The house still drafts in air from the outside in some areas. But nothing like it was when we moved in.

You can actually order the units online. NuTone/Broan have them on their website. Just make sure that you size the fan properly for both baths. The good thing is that you can also place a box in a room that always gets a funk smell.
 
1 - 12 of 12 Posts
Top