fitting of uPVC windows

[RickH]

I have 2 uPVC (1200 x 600) windows (non openers) to be fitted into a wood construction out building.
Window opening is fully constructed with appropriate lintols - so no problem there, and with a 5mm on all sides clearance.

The reveal is effectively solid wood - cavity closed at reveal.


My intended sequence is ...

# Fit cill ... pack to make it 5mm up off horizontal timber - screw fix
in place with a couple of 6 x 100mm csk screws
Q .. do I just pop these through inner (rear) chamber of cill, csk slightly into top face of cill

# run in bead of silicone against the cill upstand

# put frame in place against his wet silicone.

# fix frame to reveal with 6 x 120mm csk screw - frame packed to make
sure screws do not 'bow' frame on tightening.
Q .. do I screw direct through box section (appropriate pilot hole) ..
or do I use a clearance hole in PVC box section to allow screw to pass
though top section and bite onto steel box section - covering with a cap
.... thought this may not be needed as screw heads are all hidden when
glass is in place anyway.

# thinking of using 4 screws - 2 per side each 150mm in from top & bottom

# Also fix bottom of frame to cill with 5 x 40mm ... i.e. a fix to the cill rather than right through to wood frame.

Then fit glass, and then silcone frame to opening all round, inside & out.

Thinking of using standard 'Gold Screws' ... no need for Frame fixings or Tapcon screws .. as all fixing is direct into wooden frame.

Does this sound correct ?

I know some simply use expanding foam, but my neighbour used this and is bowed the frames as it expanded & set

 

[martyheidi]

you seem to have the right idea but make sure that you also seal from the upstand at the back of the cill to the front of the timber on the reveals on the ends of the cill ,otherwise if you don`t you will get water ingress, you could get capillary action getting water through to the inside and you will never find out how it`s getting there unless you remove the frame, i had this soon after i started fitting windows for a living on a dormer window and couldn`t understand how i was still getting a leak so removed the frame to find it had travelled along the back of the cill to the end and went inside the property,so if your going to seal the back against the upstand also do the ends of the cillthe after the frames in seal down the sides as normal

 

[RickH]

good point ... so I'll run a bead across back of upstand, and also back to front at the reveals ... i.e. 3 sides. of a square