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Resealing between External Window and brick -Help Please

  • 05-09-2023 3:07pm
    Registered Users Posts: 100 ✭✭

    Firstly I'm a complete novice.

    My house is about 22 years old. I am trying to improve on air leakage around the house as a DIYer. Not make it airtight but improve it. I would pay for some jobs to be done but I just can't get anyone interested in the work or even to give me advice. I also emailed a number of window installation places and can get neither a quote or information from them.

    I have managed to remove and replace old external sealant around one window and two french doors. Took alot of learning and time. I am now about to tackle a large floor to ceiling bay window. It does extend over two floors but I only feel able to work onthe ground floor for now. I have a few questions. I will attach photos below to help.

    One side of the window just has mortar between the redbriick and window frame. No sealant at all. The mortar fills a gap of nearly 2cm. It is porous and perishing. There were two holes that I could see and when i placed a screw driver into them it went straight into what seemed like an empty space. I used expanding foam in the two of them until I saw the foam protrude from the hole. Used a third of a can in a small area. See photos.

    On the other side of the window there appears to be a similar gap size between brick and fraome. There is sealant over some of the mortar but it is totally shrunk and cracked. I tried remove some of the sealant and it looks like this side has some mortar and some sealant attempting to fill the gaps. See photos.

    1. Should I drill holes in the mortar and try insert expanding foam? how far apart for the holes?
    2. The width from brick to frame is nearly 2cm - how can one apply sealant to this? The mortar has holes/cracks/very porous so I am assuming I need to do this?
    3. I presume I should remove the old perished sealant on the rhs?
    4. The base of the "uPVC window ledge" shown in a photo is just above ground level and also has no sealant and many gaps. I presume I should try to seal that too, will be very difficult to access!? The floor on the inside of that door/window is very cold in the winter despite my trying to seal between frame and internal concrete floor.

    I would really appreciate any help on this. I know the installation of windows is done alot better these days but the cost to remove good windows and replace them is too much for now. I am trying to seal up any other entry points like pipes and cables.

    The vents are a work in progress. Putting in pipes into somewhat irregular rectagular vent holes and sealing around the pipes to avoid cold air penetraing down into the plaster board.


  • Registered Users Posts: 6,953 ✭✭✭10-10-20


    Good to see you taking the time to tackle these types of jobs. Even if they don't feel like the add much value now, you'll feel it on a cold and windy night.

    A word of warning about expanding foam - you have to use that sparingly especially around windows or reveals as it has been known to push reveals outwards if over applied. If you must use it, drill holes around 10cms apart and fill them up in stages, skipping a hole, waiting an hour for the foam to fully set and then filling the skipped holes.

    For that cracked/incomplete piece of mortar in the 3 & 4th photo I'd get a small bag of rapid-set cement and make up a mix of 4.5:1 sand and cement and patch those up. Dampen the area first then fill it in. Let it set for around 20 mins and then rub it with a slightly damp brush or piece of damp foam. Give it ~3 days and then seal it off with the sealant.

    As for sealing the gaps, you probably know this already, but use a "low modulus" window and frame sealant in your favourite colour. After applying a good thick line of it, let it sit for around 5 mins to develop a skin and then give it a spray of water and washing-up liquid and use a finger then to lightly set the sealant into the wall and frame.

    Good luck.

    Post edited by 10-10-20 on

  • Registered Users Posts: 100 ✭✭Mumser

    Thanks for all that helpful information 10-10-20🙏

    With respect to the low upvc ledge shown in the first two photos, should the gaps underneath be filled? There are many of them and some large ones. There is only 15cm between the gravel/ground and the ledge so it’s going to be difficult to access. It will be invisible to the eye so wondering if there’s an expanding foam that does not need coating to protect from the elements that might do this task better/more easily?

    The amount of sealant required along the vertical edges of the windows/doors will be a lot given the width I need to seal from the brick to the frame. Last 3 photos. Do I run two adjacent thick beads? Or is there a better way? Don’t laugh but my fingers are small! I have tried using smoothing tools elsewhere but I find using my fingers way better to do seal, especially over irregular surfaces.

    Depending on the answers to the above queries I may change tack again. This window stretches over two stories and I am now thinking of trying again to find a professional to do the job. I would not be comfortable doing this work on a ladder two floors up! What type of tradesperson do I look for? I could then try request them on the sticky at the top of this forum.

    Thanks for any help.

  • Registered Users Posts: 1 DaymoKK

    Hi there, I've been an installer of windows, doors etc as well as a multi trade operative in the construction industry for over 25 years. I work for myself, mostly doing small jobs these days.

    I saw your post and, in addition to the good advice already given, I would recommend a product from Soudal called repair cement. It comes in a tube like silicone, to be applied using a gun, it's a mix of cement and glue which is ideal for bridging gaps and sealing between frames and brickwork/ render.

    As with most things, practice and technique is key to a good finish. Basically you gun down the gap and then with a small paint brush and plenty of water, point the repair cement to a smooth finish. Make sure you remove any of the water and repair cement from the frames immediately using wet wipes as it can stain if left to dry. It can be applied over the top of expanding foam and is water resistant when cured. I'm not sure what the recommended maximum gap is for the product but I have used it to seal large gaps between frames and stone walls on 100+ year old buildings successfully, it's all down to patience and technique building up the coverage.

    I don't know where you are located but with regards to not being able to find anyone interested in the work I'm based in South Co Kilkenny and would be happy to take a look if you're not too far away.

  • Registered Users Posts: 6,953 ✭✭✭10-10-20

    Hi, good info there, I had not encountered that product before, but I see that it's available in lots of locations and isn't overly pricey.

    One thing that I'll add is that as Soudal Repair Express Cement isn't flexable, the gap between the cement and the window will still need a sealing with a window/frame sealant.

    If you do go piping the filler product in yourself, cut a large enough opening in the tube's applicator and then squash it so that it's oval, that way it will apply easier to the larger gaps.

  • Registered Users Posts: 100 ✭✭Mumser

    Again useful information from you both. Thank you.

    @DaymoKK I will try direct message you to discuss but I think I’m too far away.

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  • Registered Users Posts: 100 ✭✭Mumser

    As an update, and to help others with similar work, I used the product mentioned above and it worked brilliantly. A big thank you to both @10-10-20 and @DaymoKK . As advised take your time experiementing with the application and you'll get the hang of it. Using plenty of water with a brush works well to finish it off.

    My next step is to apply the sealant in a few days time. I hope to use Sikaflex EBT. I tend to use my fingers to smooth/tool sealant on rougher surfaces, like brick and mortar, but I cannot find out what liquid I can use, for dipping into, to help with this product. I have searched online so if anyone has used this please let me know?

    This is a big job for me and the removal of sealant is a pain so I don't want to have to repeat for a long time. If there is a suggestion of a better sealant to use (considerong the the gap between frame and brickwork is up to 1.5cm to 2cm) please let me know.


  • Registered Users Posts: 6,953 ✭✭✭10-10-20

    Hi. To remove the sealant, get a painter's scraper, a bit like this one:

    You don't need to remove absolutely all of the old sealant, but just as far back as you can. Just don't dig into the window frames as that's a wood effect foil on the external part of the PVC and it will damage. But the correct use of that scraper will avoid some of that damage.

    In terms of liquid for dipping - I presume you mean fingers to keep them wet? Then it's standard water with a few drops of washing-up liquid. And have paper towels ready, that stuff does stick to fingers. Test out your method on a hidden piece, it's a bit of a tricky job to get very neat.

  • Registered Users Posts: 6,953 ✭✭✭10-10-20

    Oh and well done on getting this far. Post up a photo of the finish which you got of the Soudal Repair Express Cement, I'd love to see how it worked.

  • Registered Users Posts: 100 ✭✭Mumser

    Here you go! It's got be covered by sealant so I didn't make it prettier!

  • Registered Users Posts: 6,953 ✭✭✭10-10-20

    Oh that's a big improvement! That stuff looks good.

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