min pitch / fall / slope of window sill ?

[marmic]

Hello all,

 

Getting close to making decision on aluclad windows and doors (for passivhaus high performance) - but can't find anywhere in regs / nhbc etc what the min pitch needs to be for window sills. Anyone please?  (for England if that makes any difference)

 

Timber frame structure with flat reveals. Window frames will be set mid span of insulation from which it's circa 202mm to face of timber cladding.  The sill itself (which is aluminium RAL finish with upstands at ends as well as back) will be circa 195mm allowing for a 30mm overhang*

 

* another one that seems to be grey area - is 30mm correct?

 

here's hoping somebody has found the official answers?!  many thanks,  

 

 

[nod]

I would imagine that the minimum pitch is hardly any and most will be a standard pitch 

[marmic]

thanks Nod, spoken to a building control surveyor today - he tells me there isnt any reg that covers this - bonkers! when there should be something there isnt, yet many regs are simply rubbish! have been talking to likely window installer again since, they aim for 5deg, albeit ours will be 4 due to depth - but fine as has upstands to rear and sides (ends) to acts as a tray. and have clarified fitting details.  better than packer under window as weakens the thermal properties. He even said he's seen flat or sloping wrong way! No surprise there.

[bmj1]

1 hour ago, marmic said:

thanks Nod, spoken to a building control surveyor today - he tells me there isnt any reg that covers this - bonkers! when there should be something there isnt, yet many regs are simply rubbish! have been talking to likely window installer again since, they aim for 5deg, albeit ours will be 4 due to depth - but fine as has upstands to rear and sides (ends) to acts as a tray. and have clarified fitting details.  better than packer under window as weakens the thermal properties. He even said he's seen flat or sloping wrong way! No surprise there.

Proper construction drawings would show it sloping away, so I don't think building regs is really needed here, but agree it wouldn't hurt.