1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Small gaps around upvc windows & wall

Discussion in 'Home and Garden' started by Magic_x_uk, 19 Mar 2018.

  1. Magic_x_uk

    Soldato

    Joined: 11 Oct 2005

    Posts: 5,469

    Location: Derbyshire

    Hi. Noticed over the cold spell lately that we have small gaps around where the wall meets the upvc windows (inside)

    Is normal sealant suitable for this repair and paint over? It’s very slight. But obviously somewhat unsightly.

    I was thinking Just mask either side. Run a bead of silicone down. Smooth over. Remove masking tape and paint if required ?

    Thanks
     
  2. Thebug

    Wise Guy

    Joined: 17 Feb 2007

    Posts: 1,895

    Location: Walsall

    Decorators caulk is what you want as you will struggle to paint silicone
     
  3. Skillmister

    Capodecina

    Joined: 3 Oct 2009

    Posts: 19,643

    Location: Wales

    I've been round all mine with caulk as the gaps were pretty significant in places :o
     
  4. Magic_x_uk

    Soldato

    Joined: 11 Oct 2005

    Posts: 5,469

    Location: Derbyshire

    Okay caulk it is then. Didn’t realise silicone couldn’t be painted.
    Thanks guys.
     
  5. Armageus

    Don

    Joined: 19 May 2012

    Posts: 11,724

    Location: Spalding, Lincolnshire

    I'm also in the same boat (noticed the draught during the cold weather), however don't think caulk is as waterproof/long lasting and was planning on using a frame sealant (as I believe that's what was originally used - it has a rubbery texture) e.g.
    https://www.screwfix.com/p/dow-796-upvc-silicone-sealant-brilliant-white-310ml/40004

    Thinking with some proper tools and masking, a neat job should blend in around the window anyway and not need painting.
    https://www.screwfix.com/p/vitrex-sealant-remover-profile-kit/82791
     
  6. kinobestew123

    Wise Guy

    Joined: 6 Feb 2008

    Posts: 1,711

    When you say that you've noticed over the cold spell, do you mean that you've noticed because there is a draft coming through?

    If so, then it probably means that it isn't sealed on the outside properly which is the main thing that you'll want to fix.
     
  7. Armageus

    Don

    Joined: 19 May 2012

    Posts: 11,724

    Location: Spalding, Lincolnshire

    Yes noticed it due to the wind blowing directly at the windows and can feel a draught around the edges of the UPVC frames.

    Haven't really looked at the outside, but the inside sealant likely hasn't been replaced since the windows were installed (20 years ago???) and is all cracked and discoloured anyway, and could do with a cosmetic refresh as much as anything.
     
  8. kinobestew123

    Wise Guy

    Joined: 6 Feb 2008

    Posts: 1,711

    Makes sense.

    Just to add, our walls are plastered up flush to the frames so we don't have any caulk/sealant on the inside. Could you not do the same with wall filler or are your windows smaller than the plaster opening (if that makes sense)?
     
  9. Magic_x_uk

    Soldato

    Joined: 11 Oct 2005

    Posts: 5,469

    Location: Derbyshire

    What do you use for the outside then. Just brown or white weatherproof silicone sealant.
     
  10. Buffman

    Sgarrista

    Joined: 4 May 2007

    Posts: 7,711

    Location: Warwickshire


    Thanks I need to do this to my new doors and both these products look spot on (y)
     
  11. mrbazmondo

    Hitman

    Joined: 10 Apr 2008

    Posts: 914

    If you want to get a smooth finish the secret ingredient is spit. When I had my windows replaced the installers licked their finger before running it over to smooth out any imperfections. I wouldn't recommend licking your finger a second time after getting caulk on it.
     
  12. kinobestew123

    Wise Guy

    Joined: 6 Feb 2008

    Posts: 1,711

    When I did my skirting boards, I must have eaten about 1/2 a tube of caulk. :p:p
     
  13. Mark A

    Capodecina

    Joined: 19 May 2005

    Posts: 18,015

    Location: Lancashire

    With caulk its more than likely going to pull away from the pvc again and leave a hairline gap. I would do a very small, neat silicone seal and just feather up to the seal when you paint.

    If the gap is too big then a good solution is to use some 1" flat pvc bead around the window.
     
  14. Adam

    Sgarrista

    Joined: 18 Oct 2002

    Posts: 8,936

    Sorry but anyone using spit and their finger will never get a nice finish. You need to use tools like these: https://www.screwfix.com/p/no-nonsense-smoothing-tools-straight-joints/92313
     
  15. mrbazmondo

    Hitman

    Joined: 10 Apr 2008

    Posts: 914

    They help if you're doing a lot, but if you need to touch up a bit that's not quite right using a tool can easily make it worse.
     
  16. manic_man

    Mobster

    Joined: 18 Oct 2002

    Posts: 2,952

    Location: Greater Manchester

    Just a few notes as I've done lot's of silicone in my new house...

    Personally I prefer a bead of silicone inside as window frames contract and expand and plaster right up rarely lasts more than a few years without starting to look ragged.

    There are two main types of silicone sealant, low and high modulus (i.e. modulus of elasticity), the stuff that gets used in bathrooms is normally high modulus and contains a type of acid that evaporates as it cures, this is why it stinks but also why it cures more quickly. The stuff you use on window frames is the low modulus stuff so it can a) bridge bigger gaps and b) allow for more movement, these tend to be "neutral cure" so take longer to cure but don't stink the house out. You tend to find house builders use the high mod stuff on the inside as its cheaper and it's what they have loads of, but then that's why it quickly peels away from the wall as the frame moves in the temperature changes. Only downside is the high mod "bathroom" stuff tends to dry to a brighter white finish but I prefer a neat/non peeling bead that is slightly duller personally...

    I personally now use the Dow Corning "for upvc" stuff linked to earlier, I also use the "original" silicone smoothing tools, the "Fugi" kit, to be honest most of these tools are similar but the Fugi kit comes with lots of different profiles and are made of good sturdy solid silicone themselves. You can use whatever silicone you like though as long as it is low modulus neutral cure. Try and avoid non silicone based stuff though, some "frame sealers" are basically glorified caulk and won't last anywhere near as long.

    My general technique for window frames is:

    1) Remove any old sealant
    2) Patch up with patching plaster/filler of your choice to the window frame edge but leaving a small gap if possible (1-2mm max)
    3) Mask up window and frame to the size of silicone bead you want
    4) Run the silicone into the gap, don't be stingy or try and make too small a bead
    5) Smooth with the appropriate Fugi profiler
    6) Remove tape
    7) Using tiny amount of washing up liquid in cold water (not spit!!! It contains bacteria, you just need a surfactant to provide a barrier between your finger and the silicone and washing up liquid is much better) i wet my finger and smooth the edges left by the tape and any tooling lines with quick, decisive movements
    8) Leave to dry for at least 24 hours

    It's worked very well for me, I did some 2 years ago when I moved in and they all look good as when I did them. Of course, silicone can't be painted over so if that's your aim then you might need to consider other options.
     
    Last edited: 20 Mar 2018
  17. Armageus

    Don

    Joined: 19 May 2012

    Posts: 11,724

    Location: Spalding, Lincolnshire

    Perfect - confirmed what I was thinking, but very useful advice.

    Thanks
     
  18. Mark A

    Capodecina

    Joined: 19 May 2005

    Posts: 18,015

    Location: Lancashire

    @manic_man Good post, thats all spot on! You can get LMN silicone that is just as bright a white as the HMA silicone, but Dow Cornings offerings seem to be quite a dull, slightly off white, but its very good stuff. We used Soudal LMN for sealing windows and it was the exact sheen and colour of the bright white PVC and decent stuff.

    We didn't have time to mask off the frames, so just used a finger wetted with soapy water. Doing it every day you get it down to a fine art. On the outside we used a wooden peg that was left soaking in soapy water. But definitely better to put in the extra time and mask it all up when doing the job yourself.