Screw in door threshold/sill ?

[omph]

When installing door frames, should the door threshold/sill also be secured in with screws ? I've always wondered what could happen if there is a breach of the DPC/DPM, presumably, that's what the sill is for.

 

[ronniecabers]

The official advice from competent persons schemes ... is yes they should be fixed on all four edges.
In my opinion Always coat screws going Through cills/thresholds with silicone before screwing in as then they should then seal

 

[omph]

The official advice from competent persons schemes ... is yes they should be fixed on all four edges.
In my opinion Always coat screws going Through cills/thresholds with silicone before screwing in as then they should then seal

Thanks.
How long should the screws be though ? I have 100mm concrete screws which be used to screw in the jambs and into the lintel, but not sure if they are too long for thresholds.

 

[ronniecabers]

Depends on the substrate really, we generally use 82mm concrete screws as a rule for the cill

 

[omph]

Depends on the substrate really, we generally use 82mm concrete screws as a rule for the cill

Does that include low profile cills too ?

 

[ronniecabers]

I try not to secure through those if possible...copious amounts of silicone, but if no choice as its moving then yes or shorter if you have them

 

[omph]

I try not to secure through those if possible...copious amounts of silicone, but if no choice as its moving then yes or shorter if you have them

Maybe better to embed the the aluminium cill into mortar in that case ? Although I wonder whether the mortar may reaction negatively to the aluminium over time.