I have an existing patio cover it’s 12x15 one side attached the house the other with 4x6 beam and three 4x4posts. I want to remove the center post but the span will be to long for 4x6 beam so I need to change the beam. I’d like to do 6x6 to keep the height the same but my posts are 4x4. Can a 6x6 beam sit on a 4x4 post or must I use a 4x8 beam.

Comments

displayname t1_j27lfhd wrote on December 30, 2022 at 5:30 AM

You should hire an engineer to help you with the beam/post design and with the plans for permits. In general, a 4x10 beam would be more efficient than a 6x6 beam, but the actual size will depend on the roofing material, roof slope, and whether it needs to be designed for snow load. Using a higher grade/species lumber would also be an option to reduce the beam size.

With a 4x beam, 4x4 posts should be adequate, unless they're pretty tall. If you go with a 6x beam, 4x6 or 6x6 posts would be used, to match the beam width.

The existing foundation might be undersized to support increased post loads, and this would be another thing that your engineer would help you verify

baseballfan1192 OP t1_j27r20t wrote on December 30, 2022 at 6:29 AM

Posts are ~7ft tall. The roof is just 2x4s about 2ins apart laid across 2x6 rafters spaced about 3ft apart . I’m in Southern California so no snow

displayname t1_j27ro9t wrote on December 30, 2022 at 6:36 AM

I'm an LA-based structural engineer. Since you're in SoCal, the patio cover also needs to meet the building code seismic safety requirements. You don't want it coming down during an earthquake. This is something that the building department will need review, approve, and inspect. You should hire an engineer for this type of work

baseballfan1192 OP t1_j27tqct wrote on December 30, 2022 at 6:59 AM

What should I expect to pay for something like that?

displayname t1_j27tyr8 wrote on December 30, 2022 at 7:02 AM

Most local engineers will start their fees around $750 to $1,000. You might also need an architectural designer (drafter) to make field measurements prepare a site plan for permitting. Some designer will have their own engineers that they work with

usurping_reptile t1_j27lqa9 wrote on December 30, 2022 at 5:33 AM

If the loads work, sb ok. Check the strong tie hangers for 6x beam to 4x post.

manzanita2 t1_j2a5we6 wrote on December 30, 2022 at 7:27 PM

What is the span between the two posts after you remove the middle one ?

baseballfan1192 OP t1_j2c9c6r wrote on December 31, 2022 at 4:23 AM

15 feet between posts once middle is removed

Iseepuppies t1_j27lay7 wrote on December 30, 2022 at 5:29 AM

You could probably get away with it or find a metal platform of sorts to supplement the load bearing. If you’re playing around with that type of stuff be wary of building codes in your area as they made need approval of changes of anything more than 2’ off the ground etc. you could always go the tele-post route too and get some fancy cladding to hide it etc and could fix sag if there is any