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 2/11/2017

How much would cost to install a18x20 gable porch roof over a patio

Shingle roof attached to house with two posts bead board ceiling wrapped in allumnumn

Do you have the same question? Follow this Question

1 Answer


Ballpark general cost for this - $40-50/SF for normal roof, more like $60-100/SF for enclosed porch/patio (not including the porch or patio itself) - though if you go with a prefab aluminum canopy patio cover, awning or gazebo costs can get down into the $10-30/SF range depending on materials - as low as under $10/SF for awnings, more like $10-30 for most flat-roof metal patio covers on up to gazebo type covers at the $20-30 range (or about $10/SF less for DIY). But for a bead boarded ceiling, almost certainly close to or in the $40-50/SF range for an unenclosed gable true porch "roof" - on up to around $70/SF if you get fancy with it.

You will undoubtedly need an Architect to work up plans for this, both to get a building permit and for contractors to bid on and for the successful one to build to - and he/she can give you a better cost estimate for your particular area once you have a conceptual plan in hand.

Here are some links to similar questions with some ballpark cost info too -

I emphatically recommend CLOSE attention to where the roof runoff (from the patio cover and the adjacent house area) is going to go - all too many jobs like this get leaks at the interface. If you meant a true gabled proch roof, teed-out from the house at a 90 dgree angle, fi coming off the gable end of the house (no intersecting roof) be sure they do proper ice and water shield and flashing at the house intersection. If intersecting with the main house roof, proper valley construction on each side of the gable is critical, and if in snow country I emphatically recommend spending the extra $100 or two to put in WIDE ice and water shield under the valley flashing - at LEAST 6 feet wide centered on the valley, and I prefer 9 feet (nominal) both for greater width to protect against snow drifting damming of runoff, and also so there is not a seam in the low point of the valley. About the worst thing you can do in this sort of installation is trying to "tack on" the new roof, rather than doing enough localized tearoff of the existing roof to truly integrate the water-shedding elements.

And of course, plan on where you are going to carry the water - because not only will any existing gutter on that side have the center cut out of it (though sometimes you can divert that to the front of the porch roof), but you will be concentrating the runoff coming down the two valleys and need to get rid of that where it will not wet the patio or come back to the house foundation. And bear in mind - generally this sort of patio cover, especially if in a hard rain area or if roof runoff will be falling on a hard surface or pooled water, needs gutters too,otherwise the splash from the roof runoff can make a substantial portion of the patio unusable in rain or melting snow conditions.

Oh - an after-thought - be sure that the bead boarded ceiling is ventilated - otherwise you can count on mildew/rot up there in fairly quick order. Commonly soffit vents are put in the ceilings, and gable end or better yet ridge vents for the exit - though depending on the roof design conventional eave and ridge vents probably work best. Certainly with a teed-out gable extension roof that would be the normal solution - build like a normal attic except without the insulation or vapor barrier. And I would specify pressure treated beadboard - except maybe if you are planning on clear-finishing it, in which case treated woods do not take that well. But certainly best to use treated roof sheathing and beadboard both if planning on this lasting indefinitely.

Answered 3 years ago by LCD

Related Questions

Terms Of Use
Privacy Policy