Change to Attic Truss

[Chris M]

Is it possible to change from a standard truss attic with lots of Ws and X's all over the place to a "room in roof" or attic truss type system. I'm assuming this would mean redoing the supports so they still could bear the same amount of weight (tile roof), but would allow for rooms being made. My attic has so much area i feel is going to waste. I read somewhere that if you have the standard truss with the cross beams everywhere you can't change it. But if we can build super high skyscrapers i find it hard to believe we cant' get past this simple feat of redoing a truss system to allow for a couple rooms up there. Does anyone have any experience with this?

Thanks.

[lowspauld]

"Chris M" wrote in news:jLf_b.308$ [e-mail]:

Yes it's possible. You have to ensure that you comply with the load bearing codes whre you live. This would mean either replacing existing trusses with new engineered trusses, or cutting out support and beefing up existing rafters with side support. Not knowing your roof specs, a building center should be able to give you a plan and a quote for free.

[Randd01]

I Think it would require removing the old trusses. There are newer trusses that have the rooms built right into them although they are not huge.

[Tom Baker]

I would not trust a building center to design a retrofit like this. They use standard designs and I doubt they would take on the responsibility of field measuring and working out a sequence of work to avoid collapse. If it is an entire new roof, that's within their usual abilities.

If it were my house, I'd pay an engineer to come look at the situation and design a solution. That's not free, but it's really cheap insurance against failure.

TB

[HA HA Budys Here]

The whole point of using truss systems is the undersized lumber used for the roof rafters, ceiling joists, and the "W" ties amounts to much less board-feet lumber used for conventional ceiling/roof framing.

You can't conventionally frame a ceiling / roof / attic using the truss sized lumber. Yes, it's a horrific waste of space especially now that tall roof peaks are all the rage, they no longer equate to usuable walk-in attic space or future liveable room space. Anything that saves a builder / developer a few bucks is the way they do it.

[PJx]

I doubt you get any answers from someone who has actually done it and anyway, the real test is probably 20 years later when the roof starts wanting to move downhill. But I wouldn't have a problem with doing what you are suggesting. I'd just frame in my new addition first and then brace the hell out of the roof before I cut away the old truss system. Sounds fun to me. PJ

[Michael Daly]

What you'd have to do is remove the roof, trusses and ceiling and put in new trusses, roof and ceiling. You probably could add one new truss at a time and remove the old one adjacent, but it would likely be more expensive and a lot more trouble than just ripping the old out and replacing it.

Modifying the existing trusses in place so that they have a different pattern could also be done, but ditto the time and $ problems. It's not a trivial undertaking.

Skyscrapers cost millions to billions. If you spend that much on your house, you can do almost anything.

Mike

[Doug Boulter]

"Chris M" wrote on 23 Feb 2004:

Of course it's possible. And as other replies point out, there are truss systems that accommodate a room - but they're also very wasteful of space. The truss still has to have those interior web members, after all. They're just shifted toward the outside a bit.

However, even if you were to replace the trusses, this is a MAJOR project. You have to tear off the existing roof and trusses, which means your ceiling to the existing level is gone. Then you have to build a staircase (to Code) to the upstairs, which is often harder than it seems in terms of finding a location that works. We won't even talk about running electrical and plumbing. And how will you heat/cool this new area?

What you'll end up doing is adding an entire new floor to your house, and that's a big project. For that, you need an architect or a design-build contractor.

Of course you can do it. . .if you have more money than sense. But you'd get a whole lot less space and end up paying a whole lot more.

[Mark or Sue]

You could rip out the trusses and replace them with conventional joists and rafters (and much larger pieces of wood too). What I'd also be worried about is the window headers you have now. Were they designed for only a roof load, or a roof plus load bearing floor? This will be a pain to fix (if a fix is required) because it affects the lower floor.

Is your roof near replacement time? Are you willing to change it to a lower weight material?

-- Mark Kent, WA

[barry martin]

Chris:

CM> Is it possible to change from a standard truss attic with lots of Ws and X'

CM> all over the place to a "room in roof" or attic truss type system. I'm CM> assuming this would mean redoing the supports so they still could bear the CM> same amount of weight (tile roof), but would allow for rooms being made. M

CM> attic has so much area i feel is going to waste. I read somewhere that if CM> you have the standard truss with the cross beams everywhere you can't chang

CM> it. But if we can build super high skyscrapers i find it hard to believe w

CM> cant' get past this simple feat of redoing a truss system to allow for a CM> couple rooms up there. Does anyone have any experience with this?

Not only do you need to be concerned with the trusses for the roof but the joists for the floor! A couple of summers age we more or less did the same thing as you are considering: wanted to add a master bedroom, sitting room, and bathroom in what was the attic of the Dining Room addition (previous owner added the DR to the back of the house).

The building contractor had an architect check all sorts of loads: roof, that of the Dining Room, the foundation (that part is a crawl space). The DR's ceiling wasn't originally constructed to be weight- bearing so the joists had to be sistered. Actually joists had to be added between the current joists as were too far apart for the weight.

From what you described it appears your project would have a better result doing what we had to do here: remove the roof and rebuild to suit the new requirements.

- ¯ barry.martinþATþthesafebbs.zeppole.com ®

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