What to Know Before Finishing Your Attic

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  • Transcript

    LESLIE: Are you dreaming of the top floor of your home becoming a serene master suite or a quiet home office or even a getaway for the kids? Well, an unfinished attic can become any of these things but not before you have the info you need to know for finishing your attic.

    TOM: Here to walk us through just what we need to know before finishing your attic is Tom Silva, the general contractor for TV’s This Old House.

    Welcome, Tommy.

    TOM SILVA: Oh, thank you. It’s nice to be here.

    TOM: You know, an unused attic space is really a great place to tap into when you’re looking to sort of spread out. But it has some fairly unique structural characteristics. So, where do we start when it comes to finishing your attic?

    TOM SILVA: Well, first of all, you want to make sure that that attic space is legally usable. So, you want to check with your building code to find out if you have the right amount of headroom and the right amount of square footage. That combination is usually 7 feet wide, 7 feet high. And you want to have – it’s the – they call it the “70-square-foot rule.” And you want to make sure that you have that.

    The other thing is is you want to make sure that you have egress to get into that attic. And it can’t be a pull-down stair. It has to be a stairway that will meet the fire egress in and out of that attic: a railing, the stairs have to be a certain width. And you’ve got to – and the hard part about that is finding a place for the stairs.

    TOM: Right. Because you need a lot of room for a staircase.

    TOM SILVA: Yeah.

    TOM: Now, if we do meet those standards but now we just want to make some practical changes, say, to increase the room where we can kind of walk around without bumping our heads, now we’re talking about structural changes, like attic dormers. Pretty complicated, huh?

    TOM SILVA: They can be complicated. A shed dormer is – with a shed-style roof is obviously the simplest type. You have triangular cheek walls with a flat wall off the back. And just that angle of the roof – simple, angled roof – that would come down and it gives you plenty of headroom and it’s pretty easy to frame.

    If you get into a gable, then you’ve got valleys to deal with and everything else and it’s more complicated. And you’ve got to know what you’re doing. In both cases, you’ve got to know what you’re doing.

    TOM: Yeah.

    LESLIE: And I feel like, basically, attics are just used to store a couple of things and obviously, your insulation. So you’ve got to make sure that whatever your top-floor structure is that ceiling structure can support the weight of it. I don’t think you can just – if you can get a staircase up there, go ahead and willy-nilly build a space.

    TOM SILVA: Right. But is the floor going to have bounce in it and everything? Lots of times, the floor structure will carry the load but it’ll bounce. And if it bounces, then you’re going to have cracked ceilings and it’s not going to be able to bear the load of a bed or people walking around or things like that. So you want to make sure that the floor structure is strong.

    TOM: Now, one area that I see that folks get wrong all the time when finishing your attic is the insulation and the ventilation when they take a standard, unfinished, ventilated attic and go ahead and finish it. They kind of lose track of the necessity of ventilation, in particular. You mentioned those shed roofs. In all the years I spent as a professional home inspector, I would find, many times, those shed roofs were rotted because they basically choked off all ventilation through that space.

    TOM SILVA: Right. Because of the type of insulation that they used, the insulation would take the moisture in the wintertime, because the house is swollen with moisture and heated air. It would get through that insulation. When it hit the cold side or the underside of the sheathing, it would condensate at the high point of the roof. And the rafters would rot where they meet the ridge or wherever and in those blind spots. So it’s very important, if you’re going to use certain insulations, you have to vent over that.

    LESLIE: What about a sprinkler system when finishing your attic? I’ve heard so many times that if you’re building into a third-floor space and now it’s becoming usable space, you’ve got to have a sprinkler system. Is there truth to that?

    TOM SILVA: In most cases, you don’t have to have one but a sprinkler system is always a good idea. I think they’re great systems. I have sprinkler – I have a few sprinkler heads in my house. I had mine on stairways and stuff like that. But they’re – you know, fire is not good. My brother lost his whole house in about 6 hours that he lived in for 34 years. And if he had had a sprinkler system, who knows? Maybe …

    TOM: Well, when you have all those walls and ceilings torn open that is, in fact, the right time to make that kind of addition.

    TOM SILVA: Just make sure you put the sprinkler system – if it’s going to be a wet system, it has to be in heated space. So you don’t want those pipes to freeze up in that roof line because then you’re going to have another problem.

    TOM: And you might get a sprinkle when you least expect it.

    TOM SILVA: Yeah, exactly.

    TOM: Tom Silva, great advice. Thank you so much for stopping by The Money Pit.

    TOM SILVA: Always a pleasure.

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