UPVC Windows have gap between frame and Sill

piperm87

Hi all,

I've noticed some gaps under my window frames where it meets the window Sill, I know drainage is required but these gaps are a little on the big side for my liking and just wanted to make sure they were OK before getting them checked by the fitters.

I've attached a photo of the one gap which is on our french doors in the living but they are pretty consistent on most the windows that have been fitted, especially the 2 bay windows we have at the front- They were fitted around 2 years ago now. 

The house is also struggling to retain heat and does cool down pretty quickly and im just wondering if this could be an attributing factor with draughts seeping through.  I couldn't see any silicone or adhesive in the gap when i looked either.

Any Advice would be appreciated

Many Thanks

greenface2

Badly fitted window or door . shouldn't be any gap . you can unglazed and pack the cill up to meet the frame and rescrew . You can put a trim or quadrant inside and seal up to stop the draught . Don't seal up from outside it will block the drains 

piperm87

There's a few windows like it which is frustrating, I've only recently noticed since the increase in gas prices and me wondering why my house isn't holding the heat and thus investigating. The bay in my bedroom is terrible - I know bays have a bad reputation with heat and noise but we have curtains that don't quite reach the floor that block off the bay of a night and you can physically feel the coldness coming from under the curtains on the cold nights - Another window i'll be checking out over the weekend.

Infact i was thinking back last night and realized that we never had a Fensa cert for the work they completed and it makes me wonder if they never issued one because they knew they did a rough job - this is something i'll be chasing up with them now its on my mind.

grumbler

IIRC, a windowsill is added after the window is installed and all the gaps around sealed. I checked my windows and all have gaps between the sill and the frame.

Also, many frames have vertical holes at the bottom allowing water trapped in groves to leak down to the sill under the frame.

piperm87

From what i remember they put the window sill in first then put the frame on top and fixed it all in.

It just seems strange how the gap is that big on some of the ones i've checked that i can pretty much see straight through to the inside of the window frame / sill. The photo i've uploaded doesn't look to bad but i bet the gap is a good 5mm wide at its worst point.

Section62

grumbler said:

IIRC, a windowsill is added after the window is installed and all the gaps around sealed. I checked my windows and all have gaps between the sill and the frame.

Also, many frames have vertical holes at the bottom allowing water trapped in groves to leak down to the sill under the frame.

Generally the sill is screwed onto the frame first, before the combined sill/frame is installed into the opening.

The sill should sit squarely on the frame before screwing it on, so the sill is parallel with the frame both front/back and up/down.

Usually the sill is stepped down, so there will be a small gap between frame and sill on the front face, to allow the drainage holes in the bottom of the frame to discharge over the sill.

piperm87 said:

I've noticed some gaps under my window frames where it meets the window Sill, I know drainage is required but these gaps are a little on the big side for my liking and just wanted to make sure they were OK before getting them checked by the fitters.

I've attached a photo of the one gap which is on our french doors in the living but they are pretty consistent on most the windows that have been fitted, especially the 2 bay windows we have at the front- They were fitted around 2 years ago now. 

The gap on the front face doesn't look excessive to me, and if the gap is consistent across the different windows then it suggests that is the designed-in gap for that frame/sill combination.

What matters more is that the frame and sill are in closer contact towards the middle and inside faces, and there is sealing between the two parts there.  Once the window is installed then normally you won't be able to see the points where the frame and sill are in contact with each other.

Are you getting a draught coming from the frame area?

diystarter7

greenface2 said:

Badly fitted window or door . shouldn't be any gap . you can unglazed and pack the cill up to meet the frame and rescrew . You can put a trim or quadrant inside and seal up to stop the draught . Don't seal up from outside it will block the drains 

Hi

Great post.
A simpler  temp solution is cover it preferably with white tape for the winter - you can easily remove/adust this if any drainage probs etc - then do it properly in warmer weather.

Thanks

Section62

diystarter7 said:

A simpler  temp solution is cover it preferably with white tape for the winter - you can easily remove/adust this if any drainage probs etc - then do it properly in warmer weather.

That is bad advice.

Applying 'tape' to uPVC risks the adhesive from the 'tape' doing irreversible damage the surface of the uPVC (e.g. discolouration).

A gap between the frame and sill on the extenal face is completely normal for many window systems.  There is no need to block this gap up with 'tape' or anything else.

diystarter7

diystarter7 said:

greenface2 said:

Badly fitted window or door . shouldn't be any gap . you can unglazed and pack the cill up to meet the frame and rescrew . You can put a trim or quadrant inside and seal up to stop the draught . Don't seal up from outside it will block the drains 

Hi

Great post.
A simpler  temp solution is cover it preferably with white tape for the winter - you can easily remove/adust this if any drainage probs etc - then do it properly in warmer weather.

Thanks

Hi OP

Read the link for the best tapes for UPVC windows but I have used ordinary tape and removed it within a few months and it was realtively easy to take off. Read the link for the best tapes for the windows as a temp measure. I hope it works. You can easily remove it and adjust it if you get  any drainage probs.

https://www.q1tapes.com/en/blog/painting/how-to-remove-protective-tape-from-upvc-windows

Thanks

Section62

diystarter7 said:

Read the link for the best tapes for UPVC windows but I have used ordinary tape and removed it within a few months and it was realtively easy to take off. Read the link for the best tapes for the windows as a temp measure. I hope it works. You can easily remove it and adjust it if you get  any drainage probs.

https://www.q1tapes.com/en/blog/painting/how-to-remove-protective-tape-from-upvc-windows

That article is about the use of masking tape for protection whilst painting etc.  Tapes which would normally be in place for hours or at most days.

It does however hightlight the point about how easy it is to damage the surface of uPVC by applying adhesive tape to it.

And that is one of the key reasons why your suggestion of sticking 'tape' over a gap (which is probably meant to be there and is doing no harm anyway) was bad advice.

YoungBlueEyes

Back to work S62, hope you enjoyed the Christmas break 😉