Roofing materials

[Pocster]

My only real concern (assuming I do understand everything said above) is that if I board out the roof and then as I go do the dry verge etc. it's all going to take me "sometime" to do. Does it matter the OSB and incomplete dry verge (and indeed battons) will be exposed to some rain ????

It's a big job on your own 

[Temp]

If you use a good quality roofing membrane then it can be left exposed for a few months. I used VP400 and some of it was exposed six months with no apparent ill effect.

 

[Pocster]

1 minute ago, Temp said:

If you use a good quality roofing membrane then it can be left exposed for a few months. I used VP400 and some of it was exposed six months with no apparent ill effect.

 

The quote I have includes " roofshield" he said it was the best and recommended it . So I guess I've no need to rush 

[Crofter]

Roofshield is very high quality stuff, twice the price of what I used, and my membrane lasted most of the winter exposed- although it was tightly battened down onto the sarking.

I feel your pain about doing a whole roof on your own... and mine was probably much smaller than yours

[Pocster]

2 minutes ago, Crofter said:

Roofshield is very high quality stuff, twice the price of what I used, and my membrane lasted most of the winter exposed- although it was tightly battened down onto the sarking.

I feel your pain about doing a whole roof on your own... and mine was probably much smaller than yours

No pain no gain 

though I understand that it is meant to sag 10mm in between the rafters to allow water run off . But if I Osb the entire roof ; membrane ontop then batten - there will be no sag - its flush to the osb and tight ....... 

[Pocster]

Hmmmmm 

18mm osb is going to add some cost to 70metres square 

[Declan52]

When your ordering the tiles you will need to make sure you order half tiles. Depending on what side the interlock is on the tile, normally the left, you will have to order right hand half tiles. 

I'm not exactly built for speed and never went through the felt or broke a batten loading out near 2500 tiles. 

The dry ridge is easy to take with you as Dave says. 

It will take you longer to load out. Once you start the tiling you fly through it. I done mine on my own  in 4 days but I had 6 roof sections with 4 lead valleys and 5 roof Windows to cut in.

[Crofter]

My roof sarking is only 11mm, way easier to work with and considerably cheaper than 18mm.

The membrane just goes straight on top of the osb- any water is just going to run down the slope.

[Pocster]

1 hour ago, Declan52 said:

When your ordering the tiles you will need to make sure you order half tiles. Depending on what side the interlock is on the tile, normally the left, you will have to order right hand half tiles. 

I'm not exactly built for speed and never went through the felt or broke a batten loading out near 2500 tiles. 

The dry ridge is easy to take with you as Dave says. 

It will take you longer to load out. Once you start the tiling you fly through it. I done mine on my own  in 4 days but I had 6 roof sections with 4 lead valleys and 5 roof Windows to cut in.

Can't I just angle grind wholes for halfs ??

[Pocster]

37 minutes ago, Crofter said:

My roof sarking is only 11mm, way easier to work with and considerably cheaper than 18mm.

The membrane just goes straight on top of the osb- any water is just going to run down the slope.

Ok ! I'll look for the cheapest osb I can get at 11mm !

[Declan52]

30 minutes ago, pocster said:

Can't I just angle grind wholes for halfs ??

Yeah but will save you time you don't seem to have. 

How good are you at cutting straight!!!

[Pocster]

8 minutes ago, Declan52 said:

Yeah but will save you time you don't seem to have. 

How good are you at cutting straight!!!

As good as you imagine !!

 

but I have the plastic verge covers ; don't they hide the cut anyway ?

[Declan52]

Yeah forgot you where using them. 

They will hide a few sins.

[PeterW]

2 hours ago, pocster said:

Ok ! I'll look for the cheapest osb I can get at 11mm !

 

You will need to counterbatten too - otherwise you will end up with water pooling on the battens

[Pocster]

7 minutes ago, PeterW said:

 

You will need to counterbatten too - otherwise you will end up with water pooling on the battens

Sorry ; not sure what you mean ....

[PeterW]

Ok so you need to run a batten in line with your joists on top of the OSB and membrane - then attach the ordinary battens to those counter battens. It leaves a gap under for the water to run down if any gets under the tiles. 

[Pocster]

5 minutes ago, PeterW said:

Ok so you need to run a batten in line with your joists on top of the OSB and membrane - then attach the ordinary battens to those counter battens. It leaves a gap under for the water to run down if any gets under the tiles. 

I see . But I thought that was the job of the membrane ???? . I've not seen any examples with counter battens - is this just because of the osb ? I.e as the membrane can't sag water could get trapped .

Edited July 13, 2017 by pocster

[Crofter]

8 minutes ago, pocster said:

I see . But I thought that was the job of the membrane ???? . I've not seen any examples with counter battens - is this just because of the osb ?

 

I guess if you had no sarking the membrane would sag and you wouldn't need counterbattens.

[MikeSharp01]

Here is a pic of our garden room with counter battens in place - if it helps, soon putting on the main battens at 90 deg to these. The roof build up is I-joists on 600mm centres, 11mm sarking (OSB), membrane, counter battens (25 x 50), tile battens 25 x 50 and then the tiles.

 

[Crofter]

That photo should be quite helpful.

TRADA recommends a minimum of 12mm counterbatten, but in practise everybody uses 25mm, probably less chance of it splitting or breaking. The battens are fixed right through the counterbatten and sarking, and into the rafters themselves, so the counterbattens are really just acting as a spacer.

[Pocster]

I see. So only necessary if I have OSB.

 

Cheers

[Crofter]

1 hour ago, pocster said:

I see. So only necessary if I have OSB.

 

Cheers

Yup. By the way, traditionally (for slated roofs), sarking was done with broad planks (11" wide sometimes); these days you would use 22x150mm treated sawn boards. But for new builds, it's common to use OSB instead because it is cheaper, faster, and gives better racking strength.

[Pocster]

Just now, Crofter said:

Yup. By the way, traditionally (for slated roofs), sarking was done with broad planks (11" wide sometimes); these days you would use 22x150mm treated sawn boards. But for new builds, it's common to use OSB instead because it is cheaper, faster, and gives better racking strength.

Hmmmm, whilst I like the thought of the OSB (i.e. something nice to walk on) I don't like the extra cost.

I might just keep to battons and make a single crawl board e.g. piece of OSB with a 'lip' so it sits over a batton - gives me a nice surface to walk on and not worry about putting my foot through the membrane or breaking my leg. Roof is 30deg incline so sounds safe too me.....

[Crofter]

2 minutes ago, pocster said:

Hmmmm, whilst I like the thought of the OSB (i.e. something nice to walk on) I don't like the extra cost.

I might just keep to battons and make a single crawl board e.g. piece of OSB with a 'lip' so it sits over a batton - gives me a nice surface to walk on and not worry about putting my foot through the membrane or breaking my leg. Roof is 30deg incline so sounds safe too me.....

 

If your roof is designed/warranted/specced to use a tenting membrane and not rely on the racking strength provided by sarking, then you can go ahead without it.

So long as you're happy that you're going to be able to work quickly and safely on the roof without it. If the tiling ends up taking much longer you might reconsider the cost of sarking

[Pocster]

13 minutes ago, Crofter said:

 

If your roof is designed/warranted/specced to use a tenting membrane and not rely on the racking strength provided by sarking, then you can go ahead without it.

So long as you're happy that you're going to be able to work quickly and safely on the roof without it. If the tiling ends up taking much longer you might reconsider the cost of sarking

Yeah. I take your point. Cost against time. One of those I have one of those I don't!