How to Install Attic Flooring to Support Storage

LESLIE: Well, Kevin in Washington is looking for some extra storage space in the attic. How can we help you with that project?

KEVIN: Yes, I want to lay a floor down so I can use it for storage but the blown-in insulation is blown in at a level that’s higher than the 2x4s on the ceiling.

TOM: Right, the floor joists.

KEVIN: Yes.

TOM: Yeah, so how do you achieve both? You’ve got to raise the height of the ceiling joists in order to get a floor over it. You cannot compress the insulation, Kevin, because if you do you squeeze out the trapped air and that’s what’s actually giving it it’s insulating ability.

KEVIN: Exactly, so how do I get the floor up …?

TOM: Is this a trussed roof or is it a stick-built roof? Do you know the difference? Is it prefabricated trusses?

KEVIN: Yes.

TOM: Alright, well you’re not really supposed to do this but I’ll tell you anyway. You can’t cut any of those trusses. What you could do is sister under the side of the bottom cords another piece of 2×4 and position that so the height is just above the blown-in. But you’re not supposed to put a lot of weight on; that’s the reason that you have to be careful here. There’s a truss – there’s a certain type of truss called an attic truss and that definitely is not what you have. But I had a condo once with a trussed roof and I actually was able to add about 400 or 500 square feet of storage space by doing exactly this. We added another 2×4 to the side of the existing truss and basically brought it up to the height of the insulation and then added some flooring over that. But again, you can’t …

KEVIN: OK.

TOM: Not a lot of weight, OK, Kev?

KEVIN: Well, it’s just furniture, books and people. (Leslie chuckles) I mean people will be up there.

TOM: Yeah, OK. Well, don’t put the water bed up there – OK? – filled with water. (chuckles)

KEVIN: OK. Thanks, y’all.

TOM: Alright, Kevin. Thanks so much for calling us at 888-MONEY-PIT.