Maximum rafter spans for a patio roof.
Porch roof beams.
If you move up to 4 by 8 you re usually allowed to span up to 10 feet between posts.
Large 8 x 8 posts are necessary for the use of supporting a porch roof.
You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths.
The tables below give maximum spans for rafters and beams.
Measure the distance between the bottom of the porch roof and the top of the ledger beams of the porch.
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Step 1 determine the load per square foot that the roof must support.
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.
The smallest beams for patio covers are typically 4 by 6.
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.
The supporting beams are painted white and the tongue and groove boards are whitewashed.
Apr 26 2018 explore christina romero s board porch beams followed by 132 people on pinterest.
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.
In areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot.
When building a porch roof asphalt shingles or other roofing material are then attached over the roofing paper and drip edge.
We added them strictly for aesthetic.
These beams are not structural.
Sheathing 1 2 inch plywood or osb is nailed to the rafters.
For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements.
Below you ll see a flat roof which you don t see as often these days.
This provides dimension for the flat roof.
Once completed roofing paper will be installed.
See more ideas about house exterior porch columns house with porch.
A 4 by 10 can usually span up to 12 feet between posts.
In the porch below you ll see a beam that goes from the front of the porch back to the house.
You can see how lovely a flat roof can be.
In general the maximum span for a 4 by 6 beam is 6 feet between 4 by 4 posts.
