how to solve a mysterious 4 year old leak

[mp3wizard]

Hi All,

In 2017 I had a ground floor extension built, a few months after this was completed I noticed a damp patch was forming on the beam, This continued on and off for a while until I decided to remove the plasterboard to investigate further, the leak proved a real mystery.

I had all the roof tiles checked on the roof a few times, and the felt etc, couldn't find any issues, eventually decided to do a test with a hose, sprayed the hose on the lead flashing where the roof joins the building and we saw it leaking, great I thought, put on flashband flashing tape over the existing lead flashing, thought this resolved everything. I've painted the beam numerous times with stain blocker paint then emulsion, when the plasterboard was still in place etc.

However this leak keeps on coming back, we identified that it seemed to leak when it was very windy and raining at the same time, i.e sideways pentrating rain, and more recently we discovered that there was a crack in the render, coming from next doors property onto myside.

It's fair to say that this leak has caused considerable stress and annoyance over the last 4/5 years, I've had to re-imburse guests as the property was a holiday let, and have had to provide rent deductions as it was leaking, and generally it effected the holiday let business i was running there for many years in terms of having the rsj beam exposed, as couldn't reboard as it kept leaking, was left negative feedback on holiday let sites etc.

I informed the neighbour next door about this several times to see if we could work it out, only more recently I think we have finally identified the issue, around 6-9 months ago if I remember rightly, he kept me waiting for around 4 months, and eventually he put some silicone sealant on the crack in the render on his side, i did mine before. Unfortunately this sealant hasn't resolved the issue. The neighbour next door has now sold his property and is due to be moving on anytime now, so isn't interested.

I had another message yesterday from the tenant saying how there's water on the floor from the leak etc, so the leak is still occuring

I have 2 specific questions that I'd like your advice on;

1 - Would anyone consider legal action against this neighbour for the damage that his property has caused mine for all this time?

2 - How would you best repair this issue?

I am thinking that it may be best to get the render hacked off on myside from the bottom to the top of the upstairs flat nearest the boundary line, perhaps a section of half a metre or less, that way it can be re-rendered and this leak on the neighbours side can't trickle behind any render, it would stop at the boundary line and the new owner can have his side re-rendered when he sees fit. Or would you think it to be better to make do for now until the new owner takes posession and we can perhaps get both properties re-rendered at the same time.

Also, on myside it is 2 freehold flats, I own the ground floor flat but own the freehold of the upstairs flat, and that neighbour owns the freehold of my flat, there is no management company, the lease is quite difficult to understand, written in ye old english, but I'm assuming that any work that needs to be undertaken to the render needs to be a 50/50 cost shared between both flats, obviously I'll have to check the specifics but as a general rule of thumb would you think it's a shared cost?

Thanks for listening to my tales of woe

 

[John D v2.0]

Is that a cavity wall on top of the beam? If so was a cavity tray fitted above the beam at the level of the flashing with weep vents to eject the water?
Also how deep is the flashing chased into the joints of the wall? It needs to be a fair way into the joints.
Yes i can see it's rendered fully but water might enter the cavity from elsewhere if there is one.
I would be interested in the window cill upstairs.

Also you shouldn't really be renting out a place with no fire protection on the steel beams, you need to double board the beam before allowing it to be used as a place to sleep especially.

 

[mp3wizard]

Thanks for your reply, I’m not sure if it’s considered a cavity wall to be honest, it’s where the back of the original house stops and they’ve built brickwork ontop of the beam up to where the original brickwork was.

I wouldn’t have thought that they did fit a tray with vents, as I never heard them mention it.

The lead flashing was about 2 inches high against the render outside if thats what you mean, they checked it was tight several times and put silicone ontop incase, I was able to create a leak inside by spraying on the lead join, so flash-band sealant tape was used ontop also.

The builder did mention the window above stating how sometimes the window fitters drill threw the cill accidentally, so that was also checked, and they put silicone sealant over screw holes just incase.

Didn’t even occur to me about the beam, haven’t boarded it until I was sure the leak has been sorted, which it hasn’t as of yet.

I’d love to get it sorted asap, as it’s been hard to watch things deteriorate.

Having a plan of action and knowing what to mention to a builder would be good, I’d hate to get the whole back of the property re-rendered only to find it leaking again. Trouble is as the leak only appears during heavy rain with wind I could have tradesmen out thinking they’ve sorted it and I get the beam boarded and plastered only for it to return again.

 

[mp3wizard]

I’m also wondering what sort of tradesman would be best to use, a general builder or a damp specialist or someone similar.

The original builders have been back many times for free to investigate but haven’t sorted it as of yet, so I’m running out of patience after all this time.

 

[HERTS P&D]

Did they use flash band?

Andy

 

[noseall]

How would you best repair this issue?

Looks vulnerable at the vertical abutment and around the base (and possible up the sides) of that window. It needed the render removing and the window out. It needed a lead tray under the window sill and an abutment flashing chasing in with a proper bell cast forming at the base of the render.

It's now going to be a horrible place to work because of the Velux etc.

 

[John D v2.0]

The lead flashing was about 2 inches high against the render outside if thats what you mean, they checked it was tight several times and put silicone ontop incase, I was able to create a leak inside by spraying on the lead join, so flash-band sealant tape was used ontop also.

Silicone is no solution, it should have been 6 inches up the wall, and a deep groove should be cut into the wall with an angle grinder and it should be poked right in and fixed in place with wedges and mortar or i think you can get a special sealant called lead mate.
However i still think the area that is in question is likely the window cill as water is more likely to get into the wall there so any shortcoming would most likely manifest there

 

[cdbe]

sprayed the hose on the lead flashing where the roof joins the building and we saw it leaking

You have identified the problem, I appreciate your frustration but I'm not sure blaming or trying to charge your neighbours is a sensible approach, especially when you're potentially going to be making a mess of upstairs! Hopefully it's a cavity wall, otherwise I wouldn't be that surprised if it turns out you've cause a bit of water ingress into the lower part of your upstairs neighbours back wall!

The last few posts have detailed how to repair this, to help you picture it, this is a fancy version of the sort of detail that should be under the window:

We are presuming that, under the flashband, the lead join overlaps and lap onto the tiles is adequate.

Avoid any builders/roofers who offer to "re-seal" it.

 

[mp3wizard]

Thanks for the info, Myself and the neighbour have a history of disputes so my judgement is probably off, at least I've vented online and haven't added fuel to the fire, your right it's more sensible to focus on the issue at hand rather than point blame at anyone else.

Yes the lead does overlap and the tiles look good generally.

So with that window tray, does it sit within the recess i.e ontop of the window ledge, or does it sit under, and how does it actually take the water away from the area, is it because it would stick out and take water onto roof tiles instead.

And from my understanding you can't just stick this ontop, you'd have to take the window out as mentioned before?

 

[mp3wizard]

I'm guessing this would be a shared cost with the neighbour upstairs, his window, but i'd benefit the most, so going 50/50 on the cost would be fair.

 

[mp3wizard]

So Just to summarise, I need the neighbours window out and then refitted with a lead window tray flashing, a cavity tray above the beam at the level of the flashing with weep vents to eject water, and abutment flashing which needs to be chased in with a bell cast beam at the bottom of the render.

And if that doesn't work, it's 100% got to be the crack in the render...

Any idea of cost or the amount of time it would take to do this? Just so I don't get taken for a mug when I get quotes.

 

[cdbe]

The lead should go under the cill and be dressed over the abutment flashing. Cavity tray is only for cavity wall (measure the thickness of the wall to determine this). There is very little space between the bottom of the cill and the roof so you will certainly need someone competent to do this.

I still don't understand why you think the neighbours should be contributing to remedial works necessary as a result of your poorly detailed extension - the original builders - definitely! I'm not sure if you can "make" the bloke upstairs have his window pulled out so I'd certainly put him back on my Christmas card list.

 

[mp3wizard]

There was a flat roof extension previously and the walls that were close to where the leak is now, were all damp with water seeming to be coming down, So I think that this issue has been going on for a longtime prior to the open plan extension I had done, the only difference being that there is a beam now instead of walls previously.

I'll need to check the lease thoroughly but from memory I think most of the outside structure of the building is a shared cost in terms of maintenance.

I have spent about 4k the last few years in contributing to new roofs for which the upstairs flat benefits, so it's swings and roundabouts isn't it.

 

[mp3wizard]

And yes your right about the builders, this is just one problem, the other issue I have is that they knocked down the party wall, failed to build it back up after, the gutter overhangs the neighbours property by 2 inches, the drainage pipe running along the side is kind of getting in the way of rebuilding the wall, the extraction fan detail wasn't put in the correct place, according to the plans approved, and I failed to serve a party wall notice, being my first project, I was pretty clueless about boundaries and building work in general so I took their lead, and now I've got disgruntled neighbours wanting to take me to court. The reason there is a single skim of brick badly done, is because I got other builders to fill in the gap, not rebuilding the wall properly on the neighbours side, so yeah I've definietly made mistakes, just looking to put things right now i'm older and wiser.

 

[mp3wizard]

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