Are counter-battens required when constructing a roof?

[jsstevenson]

Hello...

I am curious as to the requirements in Scotland on roof construction...

Proposed roof construction is as follows (bottom-up):
trusses(rafters),
9mm cladding (plywood, osb, etc...),
felt,
counter battens (vertical) - or does this go on before the felt?,
battens (horizontal),
tiles/slate,

[edit] Roof pitch is 37 degrees.

The above is what is proposed, but the question is... based on the regulations do I need the counter battens (vertical) in Scotland? If the reg's don't dictate that this is required then why would I include counter battens (pros and cons)?

Thanks for any replies and information.

 

[noseall]

is the roof pitch very shallow?

 

[jsstevenson]

The roof pitch is 37 degrees.

 

[JohnD]

You say you are putting a cladding on the roof (ply or OSB).

If you lay the usual tilers battens on this, then each batten will form a little dam to hold water and dirt.

The idea of the counterbattens is that they lift the tilers battens above the boards and felt so that water can run down under them, in the same way that it runs down the felt when it is laid on the trusses with no cladding.

BTW you might think about using Kingspan or something instead of ply, as it will insulate as well.

Is the ply because of extreme weather?

 

[jsstevenson]

John D - thanks for your reply - couldn't work out the need for counter-battens, but as usual the moment it is explained it makes perfect sense!!!

To be honest I am learning on the run... I am using cladding as I know it is a requirement within the Scottish Buildings Regulations... I have not as yet identified a cladding material that I want to use - I know for example that I can use OSB but that this is not breathable, so for example if I wanted to construct an unventilated roof (which I am not!!!) this would not be suitable. Beyond that I am still quite unsure about the different claddings available and their pros and cons. If you have any further thoughts, they would be more than welcome.

Thanks

 

[catontheroof]

Hi, you have probably finished your roof by now. I have just replaced all felt, battens and tiles and used OSB boards to cover the roof, then counter battens, then breathable felt (it's just so much lighter) . I was told counterbattens (used 18 x 25 mm counterbattens) also provide the necessary ventilation above the boards. If you felt above the counter battens, you automatically have a trough to allow water channelling into the gutter. However the rep selling the felt told me it doesn't really matter with the breathable felt. Felt over the counterbattens does I think make more sense though. Another important point is to provide adequate ventilation in the roof space from eaves to ridge to avoid condensation.
Have fun!