Standard/best practice for upvc sill and upvc framed doorset…

19 Feb 2016
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United Kingdom
Hi all,

Would greatly appreciate some advice on the following please.. :

When fitting a new door sill (upvc / 150mm) and pre-hung doorset (upvc frame with a low-level aluminium threshold), which of the following would be ‘standard/best practice’.. :

- Bed the upvc sill on the sub-sill (brick/mortar) first and then place/position the doorset on top;


- Fix the upvc sill to the base of the threshold/frame first and then place/position the whole/complete set on the brick/mortar sub-sill..?

Many thanks in advance..!
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I'm going with option 2!

Hi phatboy,

Thanks for the response.. much appreciated.

A couple of pics of the door/frame/sill that’ll be replaced.. :
door.JPG door2.JPG

The frame will sit in single skin (half brick) wall (and sub-sill).. There’s no brickwork above the head of the frame. Frame will abut the outer-leaf of the main house cavity wall (to the right).

I came across the following two videos on youtube when I was looking for some installation tips… this led me to submit the OP above :
from around 3:12
from around 2:22 & 2:58

Have a look at the vids if you get a moment.. Let me know your thoughts/views incl their methods bedding the sill on the sub-sill..

Thanks again..!
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If you dont have enough room to seal under the cill after the door is fitted then I put the cill in first bedded down. Looks like you have enough room to seal it afterwards though.
Turn the door on its side and see how your threshold sits on the cill, Some are flush and some the lip protrudes internally by about 3mm.
Dont forget to seal the back edge and the 2 ends of the cill.

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