Door Thresholds for new build

eoin8

I'll be getting my windows and doors fitted shortly in new build, company who is installing said to pour sand and cement at door thresholds and leave 40mm below FFL. However a couple of experienced tradesmen have said I'd be better to wait till doors are in and to pour the thresholds as I'd get a better more watertight finish. Anyone any opinion on the best way to go about it?

fatty pang

eoin8 wrote: »

I'll be getting my windows and doors fitted shortly in new build, company who is installing said to pour sand and cement at door thresholds and leave 40mm below FFL. However a couple of experienced tradesmen have said I'd be better to wait till doors are in and to pour the thresholds as I'd get a better more watertight finish. Anyone any opinion on the best way to go about it?

The door threshold should be placed on a permanent structure. Doing anything less risks damage to the threshold from construction traffic and will risk having an ineffective weather seal.
'Back-filling' as described is prehistoric.
Do you have an architect/technician ? Is there a detail provided ?

eoin8

fatty pang wrote: »

The door threshold should be placed on a permanent structure. Doing anything less risks damage to the threshold from construction traffic and will risk having an ineffective weather seal.
'Back-filling' as described is prehistoric.
Do you have an architect/technician ? Is there a detail provided ?

I have an engineer who is signing off the various stages, there is no detail provided.

mickdw

Get a solid threshold in prior to door being fitted.
That way, you can ensure that dpc can be properly installed and very importantly, the door fitting guy can securely fit the door knowing that no further messing will be taking place one he is of site. The old style of sticking the door up on a couple of loose blocks then taking them out and pouring a concrete threshold after was just messing really. One major issue is that the door fitter would have to fix straps both inside and outside to try to adequately hold the door in position as opposed to only fixing internally. This resulted in messed up vertical doc.

eoin8

mickdw wrote: »

Get a solid threshold in prior to door being fitted.
That way, you can ensure that dpc can be properly installed and very importantly, the door fitting guy can securely fit the door knowing that no further messing will be taking place one he is of site. The old style of sticking the door up on a couple of loose blocks then taking them out and pouring a concrete threshold after was just messing really. One major issue is that the door fitter would have to fix straps both inside and outside to try to adequately hold the door in position as opposed to only fixing internally. This resulted in messed up vertical doc.

Ok , that makes sense alright. So what would be the best method of pouring the solid threshold to eliminate cold bridging damp etc.

BryanF

eoin8 wrote: »

Ok , that makes sense alright. So what would be the best method of pouring the solid threshold to eliminate cold bridging damp etc.

an architectural technician would be best to design a threshold detail to ensure thermal continuity;)

what about using some thermoblock's or similar, which can build-up the rising wall from bottom of floor insulation level to underside of threshold.
ive spec'd quinlites in the past but contractors don't like them as they can be brittle when fixing down the threshold

DeeJunFan

You could also use compact foam