uPVC frames, cills and silicone

[Andy Burns]

I have some new windows ready to fit (from the Dunster House site recommended here), if the weather is as forecast, I expect to fit the first couple of easy ones (small, no openers, garage rather than house) tomorrow.

Most (all?) installation instructions I've seen on the web say to silicone along the upstand at the rear of the cill before screwing to the frame (obviously to ensure the drain holes whih are only at the front of the frames able to drain freely onto the cill).

But the brief instructions supplied by the manufacturer say to use *no* silicone, I don't really fancy such an easy path for wind to blow rain under the frames. I've queried this with them, asking if why not seal the upstand only, and they just trotted-out "follow our instructions" with no additional explanation.

Can anyone think of any reason (other than them arse-covering against numpties squirting silicone all over the cill and blocking the drains) to *NOT* silicone at the back of the cills?

What would you do dear DIY-er?

Bonus question: OK, so it's personal taste, but Would you cut horns on the cills (they are supplied plenty long enough) or cut them flush with the edge of the frames? The latter seems to be the modern way, is that just an easy life for the cowboys, or does it make the job super-fiddly?

[tony sayer]

In article , Andy Burns scribeth thus

JOOI how is this affected by all the FENSA stuff thats to say doesn't it have to be FENSA installed in order to meet building regs etc?..

[Andy Burns]

Using a FENSA approved fitter is one way to do it, you can do your own BR application (retrospectively if necessary, in which case keeping evidence that e.g. frames and glass are to spec, cavity closers and/or lintels are in place would be sensible, toughened glass is fitted in all necessary places etc.)

[Tim Watts]

On Thursday 12 September 2013 21:56 Andy Burns wrote in uk.d-i-y:

I used no silicon. It's fine as the frame sits tight to the cill along the back edge as it has a lip.

However, it would do not harm to run a bead along the back edge. leave the front clear and make sure you do not get silicon into the drain holes in the frame underside.

Can't answer - I matched the cill as I had no choice. I do know that superglu (gel type) is the correct way to fix the end caps to the cill. I used silicone which worked but I had to clamp some of them. I found that out later.

I had the Dunster House windows too. If you have trouble with the beads (mine were quite stiff to pop in - though IIRC they sell frames based on 3 different make of extrusion so yours may be different!) I dipped mine in warm water to help soften and lubricate the rubber strip.

HTH

Tim

[Tim Watts]

On Thursday 12 September 2013 22:02 tony sayer wrote in uk.d-i-y:

Technically yes - if in a house (not a workshop say) - OR notify building control if not FENSA registered.

But in reality *no one* (least of all 2 BCOs I have met) really gives a toss.

[Andy Burns]

I think I will.

I'd tried to be clear that I understood about the drain holes.

I took a trip to their "showroom" before ordering, they had Selecta Systems Advance70 frames on display, and that's what they've supplied.

Thanks for the tip.

[tony sayer]

OK thanks....

[Andy Burns]

In the end, I didn't silicone the cill to the frame, after seeing how tight and close the fit is with a screw every 250mm.

[Andy Burns]

I see they've revamped their quotation website in the past couple of days, it's quite an improvement (more WYSIWYG, fewer whole page refreshes) the price for my largest window would have risen from £576 to £659 though.