hairline crack in the middle of windowsill

bassy

hey guys how can i repair this as inside the window the plasterboard is all damp moist etc and it can only be from the hairline crack on windowsill.

10-10-20

Did you mean to upload a photo?

What is the construction of the wall, double-leaf cavity or breeze-block...? Is there a crack visible on the sill or could the damp be just condensation?

horse7

Plasterboard window sill?

bassy

https://www.boards.ie/discussion/comment/120460878#Comment_120460878

Plasterboard inside wall

bassy

https://www.boards.ie/discussion/comment/120460858#Comment_120460858

Mas concrete

10-10-20

Is the crack on the exterior as well as the interior?

Were there any recent modifications to the building or do you think that the crack has been there for a long time?

If it's an old crack and the building has settled, I'd fill it with a good quality exterior filler such as Toupret masonry-repair-filler or Sika Sikaflex EBT, but I'd open the crack up first with a screw-driver so that it's exposed and the filler can fully fill it. Then repaint the wall with a good masonry paint to keep the rain off it.

bassy

https://www.boards.ie/discussion/comment/120461615#Comment_120461615

crack is on the outside and no recent mods or work done.ye the crack is there a long time.

will up load pics of it.

bassy

https://ibb.co/7VmSF7w

https://ibb.co/f2L3xNp

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10-10-20

Is that the top of a step-ladder in the bottom photo?

Can you pull back and show more of the crack and the bottom of the window-frame?

Also, what's that spot below the sill where the paint is damaged/peeling? Can you include that in a photo taken from the ground?

bassy

https://www.boards.ie/discussion/comment/120463016#Comment_120463016

yep stepladder and thats spot is just a dryed lump of cement must have splattered and dryed from previous work yrs ago.

will get more pics tomorrow as its to dark now and appreciate your help and input...............................

bassy

i forgot to add the pvc double glazed were put in 4-5 yrs ago,but there was still the issue long before the pvc were installed,i have took pictures of the inside under the window board.

https://ibb.co/ZS25f67

https://ibb.co/dmdmw5H

https://ibb.co/8PNktNs

bassy

https://ibb.co/zHmM7fk

https://ibb.co/wSjc1QH

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bassy

https://ibb.co/WzWcZWc

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bassy

https://ibb.co/ct6z1sQ

https://ibb.co/9TQjQ26

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bassy

https://ibb.co/2s2DDYq

https://ibb.co/hY2NwRj

https://ibb.co/ZS25f67

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10-10-20

Bassy, that's a mess alright and it's bringing in dampness and causing internal humidity issues, I can see. 😣

It looks like it might be a combination of that cracked sill and the seal at the bottom lip of the window which is the cause, but the right exterior window reveal was repaired in the past and it looks like it has cracked since. That reveal problem may have happened due to spalling (water ingress into the concrete which causes the steel reinforcement to expand outwards). Really it should be looked at by a competent person/engineer, but I believe that most of the water ingress can be temporally eliminated by applying a silicon sealant to the areas.

The sealant has to be application specific such as the below - no point in doing this with bathroom silicon.

https://www.screwfix.com/p/no-nonsense-builders-silicone-white-310ml/70356

The two cracks (one in the sill and the other in the right reveal) need to be raked out so that the paint is removed and the concrete exposed. The joints also need to be fully dry. Then apply the silicon pushing it well into the cracks, then smooth off and leave it to set. The very bottom of the window where it meets the sill also needs to be done, except it just needs to be cleaned well with a general cleaner and then dried off well. Then apply a good bead of silicon along the whole joint, especially up to the walls/reveals. Again, these are only a temporary fixes, the overall problem still needs to be looked at as there could be other issues there which we just can't see.

Tell me, do you have the tools and ability to do this?

bassy

Ye I would have the tools and I'm good at diy.

What do you suggest if I was to permanently fix this long issue.

10-10-20

https://www.boards.ie/discussion/comment/120465880#Comment_120465880

See, it all depends on whether that sill needs to be replaced or not and whether that crack to the right-exterior is spalling or not. Spalling can be fixed, but it's messy as the reveal will need to be pulled off and then chipped back, the steel treated, and then re-formed/concreted.

The main thing is to stop the ingress of water into your home. Honestly, I'd go with what I recommend above (see if others have additional ideas also) and paint over it if it improves matters. If there is no flexing of the joints then it should last 15 years or more before needing repair.

Option 2 would be to get a builder in (even a lad doing a local job) and have him give an opinion.

Hopefully this helps!

10-10-20

Oh, and I'd lift that internal sill - it's already rotten and by removing it it will help you see where some of the water is coming from and help to dry it out. Looks like it's screwed in where the screw-heads were backfilled. A photo of the back-side of the window with the sill removed would help us if you do take it out as we could see if the crack is the source or whether the sill has a lip/up-stand or not.

bassy

Ok will keep you updated,but will have to be done when the weather is better and warmer.

10-10-20

https://www.boards.ie/discussion/comment/120465973#Comment_120465973

Yes, drier anyhow. But that sill could be lifted at any point.

Let us know the progress!

bassy

thats not a crack in the right reveal,thats where the new cement that was done over laps the original,it was not smoothed down to look part of the original cement.

bassy

https://ibb.co/tBNgrz4

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bassy

https://www.boards.ie/discussion/comment/120466220#Comment_120466220

i suppose there could be water getting in behind it maybe as its not completely part of the original concrete.

would i be as well to chip it out and put in some Toupret masonry-repair-filler and use the filler on the crack on windowsill as well and use proper sillicone to seal bottom of window where it sits on the sill.

10-10-20

Right, that makes it easier. Just focus on the sill gap and crack then!

bassy

https://www.boards.ie/discussion/comment/120466267#Comment_120466267

use the recommended sillicone you said for the bottom of window and use the Toupret masonry-repair-filler for crack in the window sill ye ??.

horse7

https://www.boards.ie/discussion/comment/120461374#Comment_120461374

So it's not the inside wall?

10-10-20

https://www.boards.ie/discussion/comment/120466407#Comment_120466407

I was initially thinking to use the silicon for both to be honest, but now that we know that the reveal is solid then if you want to now try repair the sill crack then use the Toupret or another good quality concrete repair filler. I only mentioned the Toupret as it was recommend on here by another boards user, but there are others out there which are probably fine too.

If you're going to use a filler on the crack then use a standard weatherproof sealant on the window-frame. Examples here:

https://www.screwfix.com/c/sealants-adhesives/weatherproof-sealants/cat850058

Needles73

I haven’t followed all the thread so apologies. Regardless of sill is that not an issue with DPC under the sill. Seems like a lot of damage for a simple crack. More like no DPC or it was damaged by builder on day 1. Only a thought.

10-10-20

https://www.boards.ie/discussion/comment/120471665#Comment_120471665

It could be 50 or more years old, that construction. Not sure how mass-concrete builders handled DPC's back then other than bitumen and the like. Also looking at the external reveals I think that there is an indication that there was a refit at some point in the past. If the internal sill comes off, we might see what's going on at the sill level.

chooseusername

That doesn’t look like a pre-cast sill, so if it was cast in situ maybe there’s no drip channel and water is tracking back to wall/sill joint. Mass concrete so unlikely to have any dpc

10-10-20

https://www.boards.ie/discussion/comment/120471935#Comment_120471935

Good point, but with that crack there it's going to be a conduit for water anyway, drip-channel or not. Would you agree?

chooseusername

https://www.boards.ie/discussion/comment/120471960#Comment_120471960

Definitely, crack needs to be filled anyway.

I’m a Tech7 fan myself.

https://tec7.ie/product/x-seal/

bassy

I think that windowsill was redone around 1989 when we had a back extension here because it used to be a mass concrete window sill like the rest of the old build of the house.

So maybe yes there's no damp proof course under neath it??.

bassy

Just been asking yes that whole window was smaller back in 1989 I look at a neighbours and mine is a bigger window,hence why the reveals were obviously done and the sill on my neighbors is mass concrete sill and thicker and he's is a smaller window like mine before it was all redone in 1989.

So yes that was all done in 1989.

Where do I go from here guys?.

10-10-20

https://www.boards.ie/discussion/comment/120472741#Comment_120472741

1. Patch-job to prevent further water ingress.
2. Get a builder to look at that and price for a replacement sill and patching/repairing the inside wall. You could probably keep the PVC window, or upgrade it if it's in budget, but the overall gain from an upgraded window in a mass-concrete house is going to be small.

bassy

That window is only in 4-5 yrs so not replacing it.

Any ideas what premade mixture I can buy to put on the inside wall and sand after.

whizbang

The correct way to fix this permantly is to completely remove the sill inside and out, fit a precast sill outside if posssible, with DPC under and up behind new sill.

Replace concrete inside. Dpc should run up about 10-15mm so frame of window is pressing down on it.

Dont bother patching the inside wall, it will just fall out.

bassy

https://www.boards.ie/discussion/comment/120475658#Comment_120475658

Would you have to take out the window to do all that ??.

bassy

seems to me by looking at this that is where most if not where all the water is getting in,unreal to think munster joinery never put a bead of selicone along the bottom of window where it meets the sill.

https://ibb.co/ggp4qRQ

https://ibb.co/rcvhfDS

https://ibb.co/CmqbxS0

https://ibb.co/gMQjcg6

10-10-20

Ridiculous alright unless they have it on the upstand part of the sill.

bassy

https://www.boards.ie/discussion/comment/120477304#Comment_120477304

That's a mighty BIG UNLESS,which doesn't look very likely.

bfclancy2

https://www.boards.ie/discussion/comment/120477304#Comment_120477304

which is where they would have put it, its not going to be visible

10-10-20

https://www.boards.ie/discussion/comment/120486470#Comment_120486470

All mine, recently professionally fitted, are sealed between the bottom lip and the sill. I also have window foam (black, slow expansion tape) at the top of the up-stand. Are you saying that this is not the correct placement for the silicon seal?

bfclancy2

https://www.boards.ie/discussion/comment/120486958#Comment_120486958

i'm saying when this was installed they probably ran a bead of silicone (if they did at all) on the top of the upstand of the cill sand sat the window on that