How To Put Roof Over Existing Deck

JohnHomeMatters

Can anyone advise me on a preferred way to put a roof load over an existing deck? I don't know if can (or should) avoid spending on an engineer for this.

Existing deck is 24 w x 10' deep, ledgered to house, rear beam is 8' back (so there's a 24" cantilever). 2x8 joists 16" oc, dbl 2x10 rear beam. 5/4 decking.

To convert the deck to a porch I need to load the roof onto the deck's cantilever (code problem).

Do I have to reframe this deck to make things work?

Thanks.

WarnerConstInc.

New posts and footings.

ScipioAfricanus

I think it will depend on what the local building and safety officials say about needing an engineer. I know that here in CA. I can "engineer" this using what is called 'conventional construction' techniques and design. You need to have a set of plans that will show the layout, how it attaches to structures and building details.

The weight of a roof really doesn't put that much load on beams and such but you may have requirements for up-lift due to wind of other factors that need to be taken into account.

Andy.

BuiltByMAC

Not sure how you build your roofs but yes, the weight of a roof does put load on beams (or, in the OP's case, 2' cantilevered joists and rim joist). Esp. when the roof has snow on it.

OP, Warner has it - new posts and footings for the roof. You can punch through the deck w/ your posts to keep them in line w/ the handrail posts but you will need new footings and lateral bracing.
You thinking shed-style or gable roof?
What's your plan on attaching deck roof to house roof?

Mac

JohnHomeMatters

To answer your question about type of roof: shed roof ledgered to wall of two story house. Not much concern for snow loading here, but I still prefer to over-build a little. Things are complicated by an easement -- the deck cantilevers an inch or two into the space over a sewer easement, which is why I'm looking for ways to place the load on the deck without new footings.

WarnerConstInc.

That would have been good information for the first post.

JohnHomeMatters

true.

RobertCDF

Roofs actually support less of a load than a deck. Most roofs (with snow load) are rated at 30 PSF LL and 10 PSF DL. Decks are usually 40-60 LL and 10-15 DL. Uplift is a concern of course so you will need some hardware. Personally I use trusses for roof covers we do because they span bigger distances than conventional builds. Plus its way faster and sometimes cheaper. It gives a nice gabled look or hip if you want that looks 100X better than a shed roof. Cap the bottom with T&G paint grade pine and paint the same color as the house trim and it looks very nice.

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steves

Can you stack the beams and have a 2' overhang on the roof ?

neolitic

The engineering is less complex
for a gable.
You can run beams perpendicular
to the house to sit the rafters on,
and transfer the weight to the
house on one end, and the existing
post/beam on the other.
The shed can be done, but if you don't
already know the engineering, you should
have an engineer or architect draw it
and accept responsibility for design.

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JohnHomeMatters

Couldn't agree more that the gable or hip looks tons better than the shed...thanks for good ideas.

Danno6102

I'm guessing the footings will not be large enough to take the additional 40psf from the new roof.

DJM

The transition where the roof extends past the corner of the house is an odd transition, or maybe it's just me. (It always looks like someone ordered the trusses too long.)

Maybe a change in pitch at this transition point would look better.( At first glance it feels like more of an intended design or a bit of character).

A two foot over hang here to cover the two feet of deck cantilever solves having to transfer the roof load at this point or at the end of the truss.

This means your pitch here is crucial. No worries though, as always careful planning will prevent problems. Your truss manufacture is capable of determining this spec and by all means should.

Simply ask that he is mindful of the length the tails will need to be cut for a two foot overhang in relation to where the soffit returns from the subfacia back toward the beam. You could easily end up too low. The change in pitch will help this also. Usually the bottom of the beam would determine your tail length and in turn the width of the overhang.

With this detail, the length of the overhang actually determines the pitch from the transition point to the end of the roof.

Made a quick drawing but not enough post yet to put it here.

greg24k

HO today become more and more creative How about hiring professionals John if you have no clue what you doing, instead of playing a guessing game with roof's, with loads, etc. even if we lay this out for you, you will not know what it means or how to apply it. Secondly you need a drawing, permit and inspectons. Do it right or don't do it at all

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We Fix Houses

Have a sit down with your local bldg inspector. I had the same issue.

Inspector required 5/8 through bolts, through the shed roof ledger then bolts in the first floor ceiling joist bay or through blocking installed between the studs on the second floor depending upon the pitch.

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