UKH

Hi all

Im building a lean-to shed on the side of my house. It will have a wooden frame, shiplap cladding and corrugated pvc roofing. Approx 16x6x8feet. Will be based on a carport design, but clad in shiplap.

What timber sizes would you recommend? I was thinking of 3x3 for the ground posts, 2x6 for support beams bolted to the house to support the roofing, and 2x4 for the rest of the framing. 
 

Also, any recommendations for flashing to the house. It is roughcast, so not keen on removing render to insert metal flashing into the brick mortar joint.  I think this is just asking for the rest of the render to blow out with water ingress.

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Sounds reasonable wood spec to me. I did similar. Just be careful to allow the wind to escape both ends so you don’t make a huge windsock. 
 

re: flashing, you want ‘flashband’

https://www.screwfix.com/p/bostik-flashband-grey-10m-x-225mm/22704

the wider the better. I think 225mm is the widest. 

hth

Not used this particular one (have used various "Denso" branded products), but recommended that OP wears disposable gloves for any self adhesive flashing jobs and the like -- and remembers to put them on *before* starting to use it! Edit: possibly even a change of gloves conveniently to hand during the job

Also, meticulous wire brush/clean as appropriate the contact area first, or it might be perfectly adhered to a flaky/dirty layer and not the wall - and fall off. PPPPPP! (prior preparation prevents p*** poor performance) and all that 

What are you supporting the posts on? A standoff of ~150mm from the ground will prevent the ends rotting.

Difficult to get a waterproof seal with Flashband onto roughcast render.

I put up similar leanto. Used 150mm flashband onto worn pebbledash but chipped out most stones and pressed the tape hard. Use flashband primer on the masonry.

My initial mistake was to stick about 35mm of the flashband onto the polycarbonate sheets and most came off with heat expansion and contraction. Put new flashband on but not adhering to roofing by sticking strip of polythene sheeting under the 35mm. Has lasted over 20 years so far.

I used 3x3 for roof beams. 2" wide might have meant I missed the right position for fixing abutting roof sheets using polycarbonate.

I would have thought that 6" depth for beams was unnecessary with light roofing.

I ll be using elevated galvanised steel supports with concrete piles for some, and bolt down metal boxes for others, depending on locations.