Advice on building a flat roof covered area, off house wall

[GmGookieMonster]

So i have a patio area i would like to cover over.

3.7m x 4.6m

The plan so far is

Flat roof
For a 4.7m length i will need 9x2 joists from what i gather

So 9x2 wall plate bolter to external wall running 3.7m

10 9x2 joists will be hung off this spanning 4.7m

These will attach to a 9x2 bearer (will this need doublin up)

This will sit on 2 8x8 timber posts.

Does this seem right so far.

Roof will be covered in osb 18mm, then epdm, may have a roof light in there aswell

The posts will sit on t shape post bases

These will sit on 2 concrete piles i plan to dig out (not sure on the size these should be but i was going with 600 to 1m deep and 12 to 14 inch sq

I was also going with joist hangers as mounting them on top of the wall plate will make the roof/celling height a bit higher then what i would like.

Any advice or info would be great please

 

[GmGookieMonster]

 

[GmGookieMonster]

 

[catlad]

Looks ok to me double up the lintel / bearer
I would tamp the holes you dig and then lay a 2' sq flag at the bottom to fill later with concrete. You can just get a piece wire glass cut to a size that fits your needs for the skylight.

 

[GmGookieMonster]

Looks ok to me double up the lintel / bearer
I would tamp the holes you dig and then lay a 2' sq flag at the bottom to fill later with concrete. You can just get a piece wire glass cut to a size that fits your needs for the skylight.

I did think id need to double up the bearer.

Bit unsure what size pile would be appropriate

Wasvalso debating the post material, whether to get green oak or just treated softwood, look isnt important, i just wanna know they will be still there in 60+ years if im still in the house

 

[catlad]

600mm square should be fine as long as the ground is good.
Oak if you want it to last.

 

[GmGookieMonster]

600mm square should be fine as long as the ground is good.
Oak if you want it to last.

Again i presumed oak but had a few people say treated softwood should last longer then me if looked after but think ill go with the oak, i know ill need stainless fixings for it, but with regards to the tshape post base i was gona wrap a bit of epdm over it so the oak doesnt co e into contact as seems a bit harder to get stainless post bases.

And was looking at doing 2inch either side of post so 300 sq smaller if possible as ive gotta cut into the patio to do it but i guess i cant just do 8inch sq holes to fit post base exact, ,

600plus deep

 

[GmGookieMonster]

For wall plate fixing

9x2 timber into part brick wall part rendered block, 3.7m span

I was going to either sleeve anchor or resin and rod. Every gap between joists alternating top and bottom if anyone could advise

 

[catlad]

As long as the wall is reasonably flat one 12mm sleeve anchor between every joist will be plenty.