Does a degree or 2 make a difference

[padstar]

I need to membrane and tile a new single story extension which is approximately 9m2 mono pitched roof.

The tiles to match existing have a minimum pitch rating of 35'. In reality is a 32' pitch likely to cause me issues in the future. Just the slightly lower pitch will allow me more room for a proper flashing detail. If it is likely to cause issues i will work to the 35'

I know the manufacturers put the minimum pitch on there for a reason but do they allow a bit for belt and braces to protect them.

 

[johnny2007]

Yes, they do.
Any figure the manufacturer gives you is not the real limit, there's always at least a 10% extra room and more.
Think of cars coolant level: I have seen levels WELL over the top and engines still running fine.
Oil level a bit more tricky, but still, a couple of hundred ml over the max won't kill anything.
With a roof I would be a bit more cautious, but 3 degrees???
Frankly, unless you get tropical storms and hurricanes where you live, i wouldn't be concerned.

 

[datarebal]

Tiles can fail due to frost. As yours will be below pitch if this happens you will be in your own

 

[^woody^]

I'd like to know too. Can you be sure to post back after a few winters and let us know how the ceiling is.

 

[frutbunn]

For the sake of a few degrees I personally have accepted this with two layers of membrane.

 

[datarebal]

They will not help you if it goes wrong.

We carry out come back work for a couple of clay tiles makers.
The first thing that is checked is roof pitch.

 

[frutbunn]

They will not help you if it goes wrong.

We carry out come back work for a couple of clay tiles makers.
The first thing that is checked is roof pitch.

It works though, I'm in B Control not had one comeback yet.

 

[datarebal]

I'm in B Control

Regardless they will not help if you break the rules.

Here its mentioned 35 degrees I'm guessing plain tiles. Concrete likely hood of failure is low.

If this is the case then it may be ok.

Clay however can fail mainly due to delamination if the roof is too flat then you are on your own.

 

[^woody^]

And any camber of clay tiles.

Double sarking may well work, but the thing is with any BCO's suggestions is that they tend to be personal opinion based solely on what they are then comfortable with to issue a certificate at the end of the job. If, the following autumn's storms or winter's snow and ice cause the tiling to leak, what then for the person living there? It's passed, the inspector approved it, but that's no guarantee of performance, and more importantly there's no comeback on the council.

 

[frutbunn]

And any camber of clay tiles.

Double sarking may well work, but the thing is with any BCO's suggestions is that they tend to be personal opinion based solely on what they are then comfortable with to issue a certificate at the end of the job. If, the following autumn's storms or winter's snow and ice cause the tiling to leak, what then for the person living there? It's passed, the inspector approved it, but that's no guarantee of performance, and more importantly there's no comeback on the council.

It works i've seen it done loads of times never had a comeback and I used to work in Pennines in the highest part of the UK after the Lake District.
See regulation 7 para 2.7.

 

[frutbunn]

Just out of curiosity would you agree that Glidevale trickle vents and roof vents installed in accordance with manufactures, BBA instructions etc would be OK in such an exposed enviroment?

 

[datarebal]

Just out of curiosity would you agree that Glidevale trickle vents and roof vents installed in accordance with manufactures, BBA instructions etc would be OK in such an exposed enviroment?

If the instructions/recommendations are followed and there is a problem then you have a case

 

[frutbunn]

If the instructions/recommendations are followed and there is a problem then you have a case

In reality they **** in, even had a new bungalow ceiling collapse under the weight of the snow in its first winter. So I stopped insisting on them.

 

[datarebal]

oh dear

 

[^woody^]

It works i've seen it done loads of times never had a comeback and I used to work in Pennines in the highest part of the UK after the Lake District.
See regulation 7 para 2.7.

It may/does work, as may a few other options, and I am not disputing the role of an experienced BCO to help out the customer.

But what I'm alluding to is that any such advice on site from a BCO comes with no strings, responsibilities or comeback. It may well be that any opinion or advice on site is given out of genuine helpfulness and may be sound, or it may be out of expedience - "Do this and I'll pass it", or "Try this I saw it done on the last job".

Now once its signed off, there are no guarantees or comebacks if the advice, the idea, does not work. Whereas, if the customer follows the manufacturer's guidelines, or the advice of the contracted builder, then if things don't work out at least there is a potential to get redress.

Now the OP has an option to fit the roof at 35°, and I can't see a valid reason no to. This "have a proper flashing detail" is a bit woolly, as he could have a proper flashing detail wherever the roof went.