Roof over my concrete slab out the back door question

[kc7jty]

I want to put up a roof over my small 8'x10' concrete slab outside my rear slider door.
I'm thinking 4 vertical 4x4s one on each corner set 20" min into concrete (I do NOT want to attach it to the house) with 2x6 headers and 2x6 (or maybe 2x4s) on 24" centers. (The vertical posts will be 2" from the existing house exterior wall & the corrugated steel roof will tuck up under the existing house roof overhang)
I'm not sure if the sometimes extreme conditions here (75 mph winds every 5 years or so & often heavy snowfall) will make me wish I built with heavier materials.
Any experience with this type of thing?

4x4s only measure 3 & 7/16" square. Are there any such thing as 5x5s for the vertical posts? 6x6s would be TOO big for this job.

[HUGH]

Here I am referring to the UK so I hope some of the materials may be available in the USA. I've constructed several outdoor things, including a gazebo, using round section poles of various diameters, more or less the whole pine tree stripped of bark and tanalised. These come as they are and look very rustic for fence posts or neatly trimmed and rounded for jumping poles and so on. You can buy flat ended and pointed end poles, they are remarkably cheap and the normal maximum length is about 8 to 10ft but longer available by request.

The idea is that you receive a greater cross-section in round poles for your money and there are no corners to splinter or snag your self on either.

As for the roof, my "carport" has stood up to 70mph winds for 4 years now and it's of 6" x 2" rafters with 4" x 2" purlins. The corrugated steel roof is only nailed on using twisted, galvanised nails which have a springy, slightly domed head. On the prevailing weather end I bent the steel down a couple of inches and used a nail about every 8" into the end rafter.

Happy construction!

[kc7jty]

Thanks, I'm hoping 2x6 headers and 2x4 purlins as you call them.

[KG4CGC]

I think he's referring to studs, vertical support beams. Ah, I'm just being silly now.

[WØTKX]

Extruded aluminum columns... this is just like my porch. Sunk in 8" round concrete caissons. The right "column" is a downspout.

[HUGH]

I resisted trying to explain each term because you'll be familiar with most but rafters are main supports, sloping from apex to gutter level on a pitched roof. In my house they are only 5" x 2" to support a heavy, tiled roof but the purlins are 12" x 4" and the rafters rest on these about halfway up their length.
Purlins are mainly horizontal and go across the rafters. In houses round our way they run from outside wall to outside wall at each end of the house and rest on all walls in between. As my "carport" roof slopes about 6" the terms apply but the rafters are larger and the purlins are mostly to nail the roof on to.

The aluminium looks pretty durable and low maintenance but doesn't it dent if you accidentally collide with it?
I wouldn't really want it near my house, it was built about 1830 and anything too modern would look stark. I'm sure it fits well with many modern houses in the USA, doesn't rust and doesn't need much other maintenance.

[KG4CGC]

Ah well, a purlin I am not so it seems.

[kc7jty]

I met with the guy who will be doing my roof today. I want to use 4, 4x4 verticals, one on each corner, but they only measure 3&7/16" on a side. "Rough cut" 4x4s measure a true 4" on each side but only come in 8' lengths here (I need 10 ft.)
Thinking about 4x6s which measure 3&7/16"x5&1/4" now. Nothing is easy.

[HUGH]

How about gluing and screwing smaller sections together, with overlaps so the joins don't come together, to make up your desired cross-section and length? (No comments on Viagra here please, readers). I use polyurethane glue for outdoor stuff, made a number of wooden gates with rough, unplaned timber and this glue fills the gaps.

Perhaps though, you'll be subject to the whims of Mr. Builder man?

[KA9VQF]

I built a deck on our supposedly rental trailer house. It is 12’4” by 8’ the roof on it is held up with 4x4’ post on each corner and there are a few in-between on each side.

The rafters are 1X6s set at 16” on center that rest on headers at each side of the narrow part of the deck. I used the fiberglass product called filon for the roof. Its is semitransparent I used the green stuff it comes in blue and green at Menard’s.

Its only been up one winter but we did get an appreciable amount of snow this winter. It hasn’t really had to survive any big wind yet but the neighbor has nearly the same roof on his deck and it has been there since before we bought this trailer.

His roof is made of aluminum and filon.