UPVC to Breeze Block - Simple Questions

Discussion in 'Builders' Talk' started by Jono123, Jan 23, 2017.

  1. Jono123

    Jono123 New Member

    Hi All,

    I have a conservatory which has two sides of UPVC (Double Glazing) in the frames and the other two walls are breeze blocks (One is a boundary wall).

    We have a bad case of water ingress coming in from the top of the roof, on the wall which is the boundary wall between the houses. I have had a quote by a professional company, but having just purchased the place our budget is a bit tight to afford the works carried out. Thankfully, on the quote the consultant listed works in simple talk:

    - Recut chase in masonry and fit new flashings.

    Would it be best to use flashband or code 3 or 4 lead flashing? Do I need to finish it off with felt etc?

    I would have to re cut the chase in the masonry, but as the coping stone is loose on the boundary wall, I could flash up the wall and over the block. Then cement the stone back down. Is this the better option for all round waterproof sealing?

    - Rake out mastic beads and reform.

    Please see the photos, which product would you suggest for ultimate waterproofing? Silicone based or cement?

    As you may note the mastic is pretty messy, when I push my finger against it at the top especially it's like a mini sponge. The top seems to be filled in with a filler, which when touched is also like a mini sponge - very flaky. The UPVC panel to the left can come off, which I suspect may have some gaps in it. I also suspect that the flashing isn't covering the area well.

    The breeze blocks are cold to the touch in this weather from the inside, and are externally rendered by a pro who lives next door. After getting it waterproofed so we have no more water ingress from the top, is there a durable plaster that can withstand these cold and hopefully hot temperatures without cracking or flaking? If so, what would you recommend?

    Thanks in advance.

    Attached Files:

  2. KIAB

    KIAB Super Member

    Usually use code 4 lead.

    What's under the present lead, I can see it's stepped down from the wall, any chance of some daytime photo's & one of under the lead, gives us a better understanding of the construction.
  3. Jono123

    Jono123 New Member

    Unfortunately, I don't have any to hand. Will take some in the morning.
  4. Phil the Paver

    Phil the Paver Screwfix Select

    Was that block wall already there.??
  5. Jono123

    Jono123 New Member

    Afraid so
  6. Jono123

    Jono123 New Member

    Excuse the mess - didn't think it'd be that mucky!

    Attached Files:

  7. BMC2000

    BMC2000 Active Member

    Your lead should be 150mm above finish of roof. What the counter flashing detail is like beneath the lead would be interesting to see.

    Can you raise the lead and take a pic off the upstanding behind it?

    Also, hat is the roof waterproofed with?
  8. Jono123

    Jono123 New Member

    Hope that these help.

    It's waterproofed with thick but semi transparent sheeting on the top. From the outside it's been sealed as per the white seal.

    Attached Files:

  9. Thughes93

    Thughes93 New Member

    I'm afraid to say that based upon the amount of silicon in use that this has been an issue for some time.

    Fundamentally the roof is not designed to work at such a low slope.

    4no copings - 2.4m for a 100mm drop would be a 2.4 degree slope which is far below the minimum requirement of 5 degrees for most systems and 10 degrees for others.

    It is possible to attain 2.5 degree systems, but these are not usually used unless specifically specified.

    I would advise taking the lead off and placing a hose at the top of the slope and letting it run for a while within the trough. You can then identify if the lead work is actually the cause, which i doubt given that it looked reasonably intact and sealed.

    You should also consider that you need a waterproof layer under the copings to direct water away from the wall, and hence the loose coping may be the cause of the issue.

    I would expect that a high quote has been given due to the uncertainty of the tradesperson regarding the location of ingress as simply replacing the lead and re-siliconing the upvc is an easy 1-2 hours work and materials are likely cheaper than you can purchase yourself.

    Undertake a hose test and get a moisture meter to see the extent of the leak - its not often coming in where you think.
    Jono123 likes this.
  10. Jono123

    Jono123 New Member

    The lead flashing seems to be ok, but at the end point it started to deflect water down and into the corner area.

    Can you link me to a waterproof layer under the copings?

    Also, I would like to plaster the breeze block both internally and externally.

    For the internal plaster, should I render and then use multi finish on top? Or is there another way to really waterproof this wall and use plaster?

    For the external wall, do you advise I use a mix of sharp/fine sand along with cement/water?

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