Garden lean to roof

[IantheWelder]

I'm looking for some advice, I'm going to build a lean to, to have a covered area in my garden. I was wondering if 600 centres would be sufficient. The area is 4.8x 4.8 and I'm planning on using twin walled polycarbonate for the roof so I've got light coming through.

 

[catlad]

Hi Ian
You can buy purpose made ali bars or go timber.

 

[IantheWelder]

Hi Ian
You can buy purpose made ali bars or go timber.

Yeah, I was thinking 4 or 5x2 by 4.8m timbers, with dwangs/noggins for strength, was just wondering if 600 centres would be strong/close enough for what I'm trying to do. My biggest worry is movement from wind as it'll be totally open on 2 sides, with my 6ft boundary fence at right angles to my house on the other 2.

 

[IantheWelder]

There will be a 2 to 3 ft gap above the fence as well btw.

 

[HERTS P&D]

Welcome to Diynot forum.

Can we have your name and your occupation please.



Andy

 

[IantheWelder]

Welcome to Diynot forum.

Can we have your name and your occupation please.



Andy

It's James and I'm a train driver, thanks for your constructive input into this thread Andy

 

[HERTS P&D]

Hi James, ROFLMAO:)

This company sell everything you need:

https://www.cabp.co.uk/

Andy

 

[IantheWelder]

Hi James, ROFLMAO:)

This company sell everything you need:

https://www.cabp.co.uk/

Andy

it's actually just some advice on the construction I'm after, whether the timber I'm using is substantial enough, and if the spacing I'm planning for the joists/trusses is ok?

Cheers, Ian

 

[noseall]

4" x 2" over 4.8m will flex like a trampoline and will beat like a sail in the wind. You'd be better off designing a purlin roof with slender rafters etc, or go with proprietary roofing systems. Also consider how you stop the whole structure racking in the wind.

 

[catlad]

Hi Ian
I've built a few over the years in timber and in aliminium .
If you want to go timber then 4x2" would be plenty in terms of weight if you could bring your support post in about a meter from the end. I built one out of 3x2" and I put 3x1" at right angles every 2' so it looked like a chess board from underneath, that was 4m long but I brought the support back about a meter so the last bit is cantilevered.
I built it like that because I knew the kids would end up climbing on it and to prevent it racking.

 

[IantheWelder]

Hi Ian
I've built a few over the years in timber and in aliminium .
If you want to go timber then 4x2" would be plenty in terms of weight if you could bring your support post in about a meter from the end. I built one out of 3x2" and I put 3x1" at right angles every 2' so it looked like a chess board from underneath, that was 4m long but I brought the support back about a meter so the last bit is cantilevered.
I built it like that because I knew the kids would end up climbing on it and to prevent it racking.

Thanks Catlad, I can't bring posts in a metre as I'm going to be using existing posts to tie to, I'm happy to bulk up to 5x2 or even 6x2, plan on having a double wall plate to tie to then a single or maybe double plate at the bottom with a slight over hang of polycarbonate with a gutter at the bottom. No problems with kids climbing but I might need to go onto it occasionally to clean upstairs windows

 

[catlad]

Your plan looks similar to what I did on the last one I did when I used 3x1" across the rafters instead of noggins.
If you use that method you will need some 2x1 batons to go over your rafter where the 3x1 goes across otherwise you will have gaps and when you start trying to fit the snap down glazing bars they will bounce. or alternatively you could notch the rafters to except the 3x1