Ask Your Question

Angie's List Answers is the trusted spot to ask home improvement and health questions and get answers from service companies, health providers and consumers. For ratings and reviews on companies in your area, search Angie's List.

Top 30 Days Experts
Rank Leader Points*
1 kstreett 240
2 Guest_9020487 110
3 Guest_9190926 105
4 GoldenKid 100
5 ahowell 95
6 KnowledgeBase 95
7 skbloom 80
8 Guest_98024861 70
9 Guest_9311297 70
10 Guest_9400529 70

*Updates every 4 hours

Browse Projects By Category

Question DetailsAsked on 7/5/2017

I'm looking to build a 14'x16' roof over a concrete patio. Need pitch, rafter spacing and leg support minimums.

All wood frame with metal roof. If the roof is 16' deep, how much of a pitch do I need? For 14' wide, do my supports need to be 16" oc? Can I go wider due to very limited weight requirements? (No snow, just shade) Will one 4x4 post be enough support if in each corner of the low end. The higher end of the roof will be mounted to the exterior wall of the house.

Do you have the same question? Follow this Question

1 Answer


Sorry - there is a reason there are Architects and Engineers out there. The former would generally be your Search the List category for this, though a Structural Engineer would likely be involved undewr the architect for the actual structural design.

It is more than the structural sizing of the support members - there is consideration of the environmental loadings (wind, snow, etc) and meeting local building code requirements as well as the strength, sizing and detailing of the members and the connections, designing appropriate foundations for your conditions, roofing framing and roofing materials and any valleys and slope appropriate to your condition, handling the runoff both so it does not wet the house/house foundation or flood your patio, etc.

Great care also needs to be taken with the connection to the existing roof, both so the new patio roof does not bear down on it or cause a separation in the roofing there, but also to handle runoff and any potential for debris blockages and/or icing. My personal preference, though existing roof eave height frequently prohibits it except with flat porch/patio roofs, is leaving the existing gutters on the existing roof and tucking the patio roof in under as a detached roof (though possibly attached for sway bracing only). In many cases, to get the headroom you want (especially if avoiding a flat roof) you need to go with a gabled roof with gable (A shaped) end facing out from the house, with valleys where the new roof ties into the existing house - which can gets its elevation well up if needed.

Do it right - you are commonly talking $30-50/SF for a largish patio roof like this, so maybe $7,000-12,000 in the "normal" case - so the maybe $1000 range for a proper design and plans and specifications not only protects that investment, but also will likely be needed to be able to get a building permit anyway, plus gives you plans and specs to use for contractors to bid on your job, plus for the successful bidder to build to.

If this is a DIY, it will protect you against a lot of common DIY mistakes and to hopefully build it so you do not fail your building inspection or have it collapse or rot away on you down the road, because it is evident that this is not something you have experience with. (I inferred that inexperience, which is certainly no flaw on your part, because almost all roofs in all but heaviest snow/icing conditions are 24" rafter spacing not 16" (which is a typical floor joist spacing), and one 4x4 at each corner is WAYYYY undersized for lateral stability and also pretty substantially so for normal design roof loads for that size roof.)

You also have the option of a prefab unit - but be sure it meets the building code for your area.

Here are a few related previous questions with answers which might also be of interest:

" target="_blank">

Good Luck

Answered 3 years ago by LCD

Related Questions

Terms Of Use
Privacy Policy