Help with a leaking window

[TopBanana]

I've got a leak coming through my kitchen window which seems to be coming through the wooden lintel. It's not a problem most of the time as that's a very sheltered wall but when the rain hits the wall so that it runs onto the lintel it seems to make its way inside.

So how would you suggest I seal this? The lintel sticks out of the wall so I'm thinking it needs a sealant of some sort on the top edge - maybe some lead flashing? Or just silicon sealant? Or even some mortar?
I'm not sure what the dark sealantly stuff currently on it is.

Here's a shockingly poor picture (not like this is a photography forum or anything!)

 

[Steep]

Get up there, dig out/clean off the old stuff and use cement to reseal it.

 

[shreds]

First off, the timber lintel should not project beyond the wall as it will just absorb all the moisture running down the wall and any water/snow resting on it. So....

1. Rake out what looks like concrete mortar and replace with lime putty mortar (sand and slaked lime)

2. Provide a lead flashing probably something like Code 4/5 lead sheeting dressed into the mortar course course above the lintel, possibly even a brick course above, then turned over the lintel itself in a manner that will ensure that water is discharged to the ground and not run down the wall or back into the lintel/window. (Don't use stick on silver flashband sealant, it doesn't last)

Ensure the periphery of the window is adequately sealed too.

Don't use silicon, it will peel and leak again

The dark black stuff looks like a pitchmastic sealant that will be ineffective, break down and trap water leading to rot of the beam. Use lead, it will last a lot longer, so long as you don't get chavs peeling it off and taking it to the scrappy!

 

[kendo1]

As Ian said, can't fault it.

Only thing is, if you don't have time to fix it up properly, or the weather does not comply, you could use a building sealant as a makeshift fix for a couple of weeks/months.

 

[OldCarlos]

Is the timber just a `feature` on the front of a steel (catnic type) lintel?

Also check the pointing higher up the wall for small cracks, which will allow the wind to drive the rain in & down the cavity.
Also check guttering/soffits etc.

 

[TopBanana]

First off, the timber lintel should not project beyond the wall as it will just absorb all the moisture running down the wall and any water/snow resting on it. So....

1. Rake out what looks like concrete mortar and replace with lime putty mortar (sand and slaked lime)

2. Provide a lead flashing probably something like Code 4/5 lead sheeting dressed into the mortar course course above the lintel, possibly even a brick course above, then turned over the lintel itself in a manner that will ensure that water is discharged to the ground and not run down the wall or back into the lintel/window. (Don't use stick on silver flashband sealant, it doesn't last)

Ensure the periphery of the window is adequately sealed too.

Don't use silicon, it will peel and leak again

The dark black stuff looks like a pitchmastic sealant that will be ineffective, break down and trap water leading to rot of the beam. Use lead, it will last a lot longer, so long as you don't get chavs peeling it off and taking it to the scrappy!

That's fantastic information, thank you so much!
It's weird that it sticks out the wall rather than being flush - would it just have been lazy workmanship when it was installed?

The position of this window is in a side passage with eaves which overhang by probably a metre and a high hedge on the other side of the walkway, so it takes quite a unique combination of wind and rain to get it wet. That's why it's lasted so many years before noticing there's an issue, but I'd like to get it sorted before the wood rots.

 

[shreds]

At a guess, the timber beam jutts out because a metal lintel has been put inboard of it, but that is pure speculation.

Any builder worth his salt would never have installed a beam projecting like that.

Looking at the brickwork, I am guessing 1930s built or much older with 9" solid walls?

The beam appears to be purely for effect and could even be cast plastic/foam. Does it sound hollow or solid when tapped?

What is the internal wall like at this point?

Sorry, there is only a limited amount of information in the photo that I can guess at.

 

[TopBanana]

Thanks @shreds
As far as I know the house is more like late 19th century and the walls are big thick solid walls like you say. The beam is definitely real wood, but I'm not sure whether a steel beam has been put in (maybe when they did the double glazing).
On the inside there is a damp patch on the left but the water was coming in through the top right hand corner. The damp patch was what made me think the beam might be wood all the way through, but maybe it's just water getting behind it.
Here are a couple of pictures with slightly more daylight.

 

[kendo1]

I see from the first pic that the bricks don't line up at the left hand edge of the window.
It looks like there are two phases of building. Is one part an extension?

The line goes right up the wall and coincides with the crack on the second pic at the top of the window.

Check that the pointing is okay along this line.

 

[TopBanana]

I see from the first pic that the bricks don't line up at the left hand edge of the window.
It looks like there are two phases of building. Is one part an extension?

The line goes right up the wall and coincides with the crack on the second pic at the top of the window.

Check that the pointing is okay along this line.

I think that's just my shoddy photography! In the first picture there's a pillar closer to the camera which is what's making it look like the bricks don't align. You can see the matching pillar at the far end of the passage way and just about make it out in the picture in the OP.
On the internal photo it's not a crack at the top right just some seriously appalling plastering done by a previous owner!

 

[shreds]

The timber lintel looks like an old railway sleeper, which were commonly 10" in width, which if applied in a 9" solid wall would leave a projection if it wasn't cut longitudinally.

The black stuff you mentioned is likely in that case to be creosote, which railway sleepers were soaked in, to resist rot, but creosote is now universally banned, due to its toxicity. It will continue to leach out of the wood. It doesn't prevent rot long term...that is why they have to ultimately replace railway sleepers as they still rot, just at a slower rate. Old railway sleepers therefore may already be coming towards the end of their life when they are offered for resale, although the way renewals take place, they will also extract many ok timbers too, as it is usually too disruptive to remove them individually.

The shoddy plastering/cracking internally may have been due to the timber rotting despite the creosote, within the wall or just thermal movement as the wood expands and contracts with the seasons and any absorbed moisture it is taking from above, requiring the past owner to try and make good.

Internally there appears to be two areas of staining; whether this is just creosote working its way through or damp penetration I cannot tell from the picture. The underside of the window head reveal to the right hand side of the internal picture looks to be uneven and plasterwork is bubbling.

It is allowing secondary defects such as damp to occur, which in turn is leading potential rot. Also it is likely laid in its weakest plane, whereby the widest side is supporting the brickwork above and therefore more likely to flex.

What would I do?

Probably in the medium term have it removed altogether by supporting the window opening, temporarily removing the window, and replacing the timber with a modern lintel (Steel 'Catnic's' are usually the most cost effective or concrete lintel), but it will be disruptive and messy. The option of covering it with lead would only be a short term protection and any deterioration in the wall would continue.

 

[beyond the blue]

I have exactly the same problem on my gable end window. I have noticed hairline cracks in the mortar joints. I was going to repoint the entire gable end this year but never got round to it. The rain has been coming from the opposite direction than usual, the wall gets soaked and wind drives the water through the hairline cracks. I'm going to spray the wall with Thompsons water seal this afternoon now it's dry and hope it gets me through this winter and hopefully get round to doing it properly next year.

 

[kendo1]

This is what I had to do with defective pointing. The inner wall was removed and I had to batten the wall out without affecting the new damp proofing.

001 by Ken, on Flickr