Box gutter - Butyl or Bitumen Flashing tape

[ant2]

Hi all,

I hope someone who has experience in gutters, or building may be able to help:

I have a box gutter between the single storey roof and conservatory.
It's aluminium and made up of 3 sections.

Since I moved in the gutter has been leaking where it joins, if you look at the picture you will see there is a bracket inside the gutter itself. - It looks like the bracket is how they have attached the two sections of the gutter together.

1.)
a)Is this normal
b.) Should it not be over lapped?
c.) Is there a resolution?

Beneath it looks like this - //www.diynot.com/diy/media/inside-conservatory.88472/full
And it looks like they used something like sikaflex EBT inbetween the two gutters, to act as a kind of seal and to hold it together.


Anyway the water is obviously coming through a pinhole gap under that bracket and it then reached that sikaflex stuff, which is now 20 years old and then continues to drip down in to the conservatory. I get a few drips per day, unless there is particularly heavy rain.

I have asked about 50 traders, Roofers, Double glazing specialists, Gutter specialists, to come and have a look at this. From the ones that have turned up, they have suggested the following
a.) Don't want to touch it
b.) paint over it in acropol/cromapol
c.) Paint it in jack black.
d.) Install a gutter liner, but after contacting said merchants, none will make a gutter line that will fit a bracket.

What I have then tried:
a.) Cromapol- it lasted a few months and then leaked again.
b.) EPDM liquid rubber, this lasted a few weeks and then it looks like grains of sand/dirt starting wearing down a raised bit of rubber and made a pinhole and started leaking.
c.) Bitumen flashing, on one side I used generic cheap flashing, with no primer and it was not bone dry. This has held up for a year, but looks to be lifting after the cold weather. - I was going to redo it this year

d.)Bostik Flash band with Bostik Flashband primer licked everywhere and wrapped everything I could see. This was installed in the bone dry and looks to be holding up to the job like glue.

2.) How long is this likely to hold up, I was hoping 5+ years


3.) What do you guys suggest is the best fix for me when I re-do the other bracket this summer?
a.) Bostik Flashband primer everywhere (I am hoping some will drip down the join)
Bostik Flashband

b.) Butyl tape, I read that Butyl is good at low temperatures and movement, which bitumen isn't as good at holding up. I have a roll of this I bought already:
http://www.screwfix.com/p/sika-multiseal-butyl-flashing-tape-grey-100mm-x-10m/38892

c.) Bostik Flashing primer + Bitumen mastic pushing up against the bracket edge to get some to potentially go underneath a bit of flexibility, + Bostik flashing over everything

d.) CT1 sealant, that apparently is flexible and doesn't degrade

4.) In the meantime while I am waiting for the summer, I actually "fixed" the leak from the underside of the gutter, by cutting out a few cm's of that glue from the whole section (which is now not holding up) and pushing up bitumen mastic in between the hole, then flashing over the section. So this should hold until the sun comes out.

5.) If someone has a better solution and is in the trade, or knows a decent one and wants to carry out a proper fix, I am in the Buckinghamshire county

 

[Mw Roofline]

I'm not an expert but I'll put in my 2p's worth.

Those brackets are pretty bullet proof as they can't move so never leak.
Are you sure water isn't getting in at the back? There is a tear in the lead.
Conservatory guttering is dead level, without any falls. If it's all connected in one loop, just dam the hell out of that join with as much gunk as possible so the left water goes to the left and the right goes to the right, plus you can lead over the top of it to help even more.

 

[ant2]

MW Roofline, Thanks for your reply.
I am 1000% sure it's coming in via that bracket. I made the two slits in that flashing that you see.
It was like this (see raised bit of flashing):

I put the slit in so that the lead sits flush in the gutter and that bit in the middle sits on the bracket. When it first started leaking I was worried because that 10cm section of lead was sitting at a right angle,( was resting on top of the bracket) it was causing water to back up towards the roof, rather than in to the gutter. The incision now lets the whole length of flashing sit in the gutter.

After sealing all around that bracket the water stops coming in, so it has to be coming from there. This is what the "good" side bracket now looks like:

As you say the box gutter is level, so water is always sitting in there pooling. Problem is there is 3 sections, even if I was to raise the entrance + exit of the bracket with bitumen mastik , there will always be water in between the two brackets (one wanting to go left, one right).
I presume you will suggest the butyl tape over the primer +bitumen flashing?
If the Butyl tape really lasts over 10+ years from your experience, to be honest i'd be happy with spending an hour every 10 years - I was just wondering if there was a more permanent fix.

 

[chappers]

fibre glass it.

 

[catlad]

Cut the bracket out and get a new ali gutter made in one piece and sit it inside the old one then dress the lead back in place.

 

[ant2]

Cut the bracket out and get a new ali gutter made in one piece and sit it inside the old one then dress the lead back in place.

Hi Catlad, if you grind the bracket out that will also be removing the gutter supports to the wall. This could/will mean it's not being supported properly, so you would have to support it underneath somehow instead.
The brackets are also what's holding the gutter together, by removing them, there is nothing holding the lengths together.
The gutter is 36ft long so I think it would have to be put in with a crane to safely get over the conservatory


Hi Chappers: I have never worked with fibreglass before, is this likely to last a lot longer than buytl + Bitumen flashing?

 

[chappers]

25+ years longer if undisturbed, but you will have to get the area, pretty well cleaned up. I have no idea how well it will adhere to bitumen primer.
The beauty is that as well as the matting you could pour resin into the area which would seal the leak.

 

[ant2]

25+ years longer if undisturbed, but you will have to get the area, pretty well cleaned up. I have no idea how well it will adhere to bitumen primer.
The beauty is that as well as the matting you could pour resin into the area which would seal the leak.

Thanks Chappers, do you have any links to a suggested Fibreglass kit to use?
I presume you just mix the liquid with the resin and paint this over all the matting, which I would wrap around the whole thing.

 

[chappers]

Just search for fibre glass roofing there are loads of them out there that will sell all the gear, in a kit form including all the tools you will need..
Personally I use a local roofing merchant, who I have known for years and beats internet prices on most things.
In simple terms its a case of mixing the catalyst with the resin and then painting it onto the matting and consolidating it with a paddle roller.
But as I said you will need to get it cleaned and keyed up so the resin bonds properly. I would do a decent area around the join and up the sides of the gutter too or if you can face it better to do the whole thing. the best advice I can offer is work methodically, do a bit of reading up about fibre glassing as there area few dos and don'ts which may not be obvious.