The tables below give maximum spans for rafters and beams.
Porch roof beams.
Patio roof beams beams can be solid lumber or be built from lengths of 2 by lumber nailed together with 1 2 inch pressure treated plywood spacers in between this forms a 3 1 2 inch thick beam that is equal to the width of a 4 by post.
The smallest beams for patio covers are typically 4 by 6.
There are many choices to consider when selecting your roof style.
Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads.
These beams are not structural.
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While many like to use the smaller 4 x 4 posts they can tend to warp after they have been standing under the weight for several seasons.
In areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot.
See more ideas about house exterior porch columns house with porch.
When building a porch roof asphalt shingles or other roofing material are then attached over the roofing paper and drip edge.
In the porch below you ll see a beam that goes from the front of the porch back to the house.
Below you ll see a flat roof which you don t see as often these days.
Porch flat roof patio roof front porch dark ceiling roof ceiling ceiling fan porch ceiling lights ceiling lighting up house porch ceiling styles the porch company beadboard collar ties exposed beams.
You can see how lovely a flat roof can be.
Maximum rafter spans for a patio roof.
Sheathing 1 2 inch plywood or osb is nailed to the rafters.
The supporting beams are painted white and the tongue and groove boards are whitewashed.
If you move up to 4 by 8 you re usually allowed to span up to 10 feet between posts.
For a porch roof the beam needs to be sized according to the maximum snow loads in your area and you must know enough about the porch design to determine how the load will be distributed and over what distance the beam will carry the load.
A 4 by 10 can usually span up to 12 feet between posts.
For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements.
We added them strictly for aesthetic.
Then attach drip edge over the roofing paper.
This provides dimension for the flat roof.
Measure the distance between the bottom of the porch roof and the top of the ledger beams of the porch.
You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths.
In general the maximum span for a 4 by 6 beam is 6 feet between 4 by 4 posts.
Cut beams to fit.