Some more questions re. shed

[Lons]

John
If you are using OSB, be careful of your rafter spacing as a lot of OSB sheet is still being supplied in 8x4 sheets (2440x1220) and you could find yourself cutting every sheet which is a pita.

My apology if that's already been pointed out.

 

[John Brown]

That'll survive 3 or 4 years of being left out in the sun and rain. I wouldn't worry about it for a second.

Really? I was under the impression that once the edges got wet it would be compromised.

 

[John Brown]

John
If you are using OSB, be careful of your rafter spacing as a lot of OSB sheet is still being supplied in 8x4 sheets (2440x1220) and you could find yourself cutting every sheet which is a pita.

My apology if that's already been pointed out.

Thanks, Lons. I'll keep that in mind.

 

[John Brown]

I keep reading that EPDM is suitable for flat or low pitched rooves. My proposed and PP approved design has a 40 degree pitch. What are the implications of this, if any, please?

 

[Fitzroy]

My only thoughts are it may slip/slump with time if it was a mono pitch, how would you fasten at the top. If it sloped both sides this wouldn’t be an issue.

Other thought is, it’s normally used because a more robust longer lasting option is not available, ie you can’t slate or tile a flat/low pitch roof.

Fitz

 

[MikeG.]

It's only ever fitted over a ply or OSB base, so it's fine on a pitch. It is glued down with a none-setting gum-like adhesive which holds it in place nicely, and you use a contact adhesive around complicated shapes or changes of pitch. One of my sheds has a c.40degree pitch and has EPDM on it. It's perfect.......but you can see the roof covering. When it's flat, you can't actually see what's on a roof. There is nothing longer lasting or more robust than EPDM in terms of single-ply roof coverings. I'd be surprised if it needed changing in 50 years time.

 

[John Brown]

Thanks both. I doubt I'll be around in 15 years, let alone 50, but I'll give it some thought.

 

[John Brown]

1. Horizontal studs?(I'm sure they're not called that...). Do I need them? If so, what spacing?

2. Internal OSB sheathing. Portrait or landscape? Shed is 3m by 4.5m by 1.9m at eaves. Wastage seems roughly equal. If landscape, I guess that answers 1.

3. Tyvek or equiv. Does it need stapling to a horizontal frame member? If yes, then I guess that answers 1.

4. When I fit the window frame, how do I line up the outside surface of the frame? Flush with the framing? Flush with the outside of the counterbattens? Somewhere else? I'm planning on waney edged larch cladding. Window frame is around 75mm deep, studs are 95mm.

5. Do I really, really need 18mm OSB3 on the roof, rather than 11mm? It's going to be a real struggle getting it up there..

 

[MikeG.]

1/ Noggins. Not absolutely necessary (but see 2/, below), but stiffens the wall up nicely and I would certainly suggest using them.

2/ Doesn't matter, but if you do landscape, then you need noggins at the level of the long edge join.

3/ No.

4/ I line up with the outside of the studwork framing, and then put a small window lining board over the counterbattens and board ends.

5/ On the top of the roof....yes. As a lining inside, then no. 9/10/11mm is fine there. Without reading the whole thread, I presume you are planning on a roof covering such as EPDM. Of course, if you are tiling etc then you don't need any board on top of the roof at all.

 

[John Brown]

1/ Noggins. Not absolutely necessary (but see 2/, below), but stiffens the wall up nicely and I would certainly suggest using them.

2/ Doesn't matter, but if you do landscape, then you need noggins at the level of the long edge join.

3/ No.

4/ I line up with the outside of the studwork framing, and then put a small window lining board over the counterbattens and board ends.

5/ On the top of the roof....yes. As a lining inside, then no. 9/10/11mm is fine there. Without reading the whole thread, I presume you are planning on a roof covering such as EPDM. Of course, if you are tiling etc then you don't need any board on top of the roof at all.

Many thanks.
Can I wrap, stuff and sheath one wall at a time, or is the strength of Tyvek compromised if I don't wrap the entire structure in one run?

 

[MikeG.]

One wall at a time is fine, so long as you leave enough overlap.

 

[clogs]

John
doing one wall at time is OK....It's the overlap u need to be aware of...more the better.....
preferance would be to do the North and West facing walls together, they get the brunt of the weather ....and there would be no join......
then do the rest as and when ur ready.....
when I worked in California the whole house was done at once but then there was a crew to do it....
Pay particular aten to the openings and their flashings....also use the proper tape.......
plenty of good how to's on line...
do it right do it once......

 

[John Brown]

Thanks. And do I need special staples?
Tape?

 

[MikeG.]

No. The staples are a temporary fixing (but left in permanently). The membrane is held in place by the counterbattens, in the same way that roof membrane is stapled first, but actually held permanently by the tile battens.

 

[John Brown]

No. The staples are a temporary fixing (but left in permanently). The membrane is held in place by the counterbattens, in the same way that roof membrane is stapled first, but actually held permanently by the tile battens.

Got it. What's your view on tape, Mike?

 

[MikeG.]

Unnecessary on a shed.

 

[John Brown]

Great. Counterbattens are 25mm, from your drawings, but 25 by 25? 25 x 50?

 

[MikeG.]

You can get away with 38x25, but it's best to use 50x25, especially if you are going to end up needing butt joints to the boarding. It's hard to get nails from two boards into 38mm.

 

[John Brown]

You can get away with 38x25, but it's best to use 50x25, especially if you are going to end up needing butt joints to the boarding. It's hard to get nails from two boards into 38mm.

Thanks. 50 x 25 it is then.

 

[John Brown]

I've made a lenght of sill/cill with a slope and a drip groove fro a shed window, but of course it projects from the frame of the shed(or it will, when I fit it). So I'm thinking that wrapping will be difficult. I was planning on supporting the sill on the "cripples"(sorry if that's an American term), but now I'm thinking maybe I need another noggin at the bottom of the window aperture, wrap and fold the Tyvek into the aperture, and then fit the sill. Am I overcomplicating this?