Post spacing for porch roof ?

I plan on putting a roof over my 25' long x 8' wide front porch. Just a simple frame with steel panels, and attached to the house on one side . Using 4x4 posts to support the header on the other side, what kind of spacing is required ? I was thinking about every 8' but thought I'd ask people with more knowledge than me. -Thanks

I don't know the answer, but don't forget to consider possible wind and snow loads.

Jim

With 4x4s no farther than 8’ on center. Since there will be nothing securing them from shifting at the base, they should be in a concrete footer or fastened to a sonotube with an appropriate bracket.

I was going to sink them 30" deep and back fill with concrete, but I just looked up sonotube and like that Idea better. Are then just as stable and solid as sinking it in concrete ?

4 x 4's get a little squirrely -I would upgrade to 6 x6's with a double header on the post ends and as mentioned, the sonotube foundation works well,allows for less heaving and easier to level posts.

Doesn't mater what size the posts are the spacing is governed by beam size and roof load, roof slope plays a part in the loading of the beam.

Never place concrete next to wood.

Rule of thumb, a beam can span about one foot for every inch of depth. 2x12 doubled can span 12' normally. 2x4 doubled can span 4' etc. with just rafter load.

4x4 don't make good posts because if they are over 6' tall they will bend/bow under load. 6x6 is preferable and when looking at the end try to pick post timber that has the heart centered in the post- it will not warp/bow as bad (if at all ) as a post with heart on one side and sap on the other.

Anytime that you bury any wood into concrete, it will rot out quickly. The concrete will act like a water proof sleeve and not allow any water that drains down inside to escape. Then the water will be absorbed into the wood.

old shade tree way before ready made brackets etc was to dig a 10 inch post hole about two feet deep.. frame the top of the hole with 2x4's making a 16 inch square. drill all the holes and set all the forms leveling them to each other. pound 3 pieces of rebar into the dirt in the hole with the top of it just below the top of the form. A fourth piece of rebar extends above the form about 4 inchs and is centered. put some hog wire panel or other steel in the 2x4 frame. do the frames with sac crete mixed up in a wheel barrow. after a few days you can drill a hole in the end of your post and set it on the rebar.

I think that people selling stuff have over complicated stuff and often you get inferior results. Trusses instead of rafters or joists for example

Follow this advice.

First, locate your windows and doors. Locate posts so they are not in the middle of either. Then find out what your longest span will be, go to the lumber yard and they will help with the sizing. Header should be laminated, atleast doubled. For more strength you can use some coil stock inbetween the 2x's.

4x6 treated is as strong generally needed on 8 foot spans.

Refer to this for starters. Then look at your local codes for snow and wind load etc. Of utmost importance is your header size and the load on the header.
Post spacing is immaterial unless you know these other factors.

Well, you said porch and that means you have floor to hold up the posts, but then you say dig & concrete ect.
you might look for these at your lumber place- they'll hold up as much as your beam on solid soil.

If you put posts in the ground,slap the creosote to them,and fill hole with pea gravel for drainage.

It is against code to use those in Pennsylvania.

Spacing porch posts has more to do with where the door is to me. You don't want a post in front of the door.
And if you are putting on a railing your posts should be at 6'. That's the common premade railing size. The 8' size gets a little wobbly in the middle.

I'm guessing that if they are against code in Indiana, that Loews won't stock them, eh?

No, the big box stores stock them here too. Not against code to sell, just to use.

They have them at Lowes here to. The average person does not know what the codes are. And Lowes recommends them for different projects.

Also, you can find a span calculator online that will allow you to input snow & wind load parameters. You didn't mention what sort of member you will be using as a header. A 4"x10" is pretty standard depending on the span. A garage door header ...say 4"x14 or 16" will allow you a larger clear span. Also check out www.simpsonstrongtie.com. Lots of handy hardware available to make things easier and more secure.

Be sure you use pressure treated material for anything in contact with the soil or concrete

i would check codes and permits - unless you are specifically skpping permits - but around here, getting found without a permit is a mean and nasty process that usually costs 2 to 3x in the long run.

post spacing is based on beam (header size)

header size is based on load from roof and rafters

most of this info is sitting in charts in code books

I'd also skip the 4x4s for anyting taller than raling

I'm so glad I live where there is not a code for everything. In rural Mo. If your stupid enough to build it and live in it, let Darwin take its course.

Supposed to get permission where i live now but i never have. Doubt i ever will either