Thread: Leaking Roof Join

They sell a foam product in the shape of corrugated iron. Would this be appropriate?

I have not had this issue, just spitballibg an idea

Was the verandah roof put up by the previous owner or done professionally?? I would say that the verandah roof isn't folded on the ends in the valleys. This is done with a pair of pliers and the material in the valleys bent up at about 45 degrees. This is done to prevent your problem, if possible the sheets need to be removed and the ends folded up. The other thing that could be causing the problem is the nails have become loose, replace them with roofing screws, if that is the case.
If you do lift the sheets to fix the ends, instead of using tape, I'd put in a bituminous foam strip between the two surfaces.
Kryn

Forget the 2 screen shots and the foam (goes hard and brittle after about 18 months).

Photos please but the chances are the verandah sheets were not "weathered" as Kryn has said. Also, you will probably find a build up of dust/leaves behind the lap of the main roof and the verandah if the main roof does not marry in tight with the verandah roof. If this is the case you need a custom flashing bent to the angle of the 2 roofs that is 73 deg with with 100mm under the main roof and min of 150mm with 20mm crush fold over the verandah roof. Use the small hex stitching screws to fix to the verandah roof, none needed on the main roof.
The other scenario is that the 2 roofs are tight fitting but expansion/contraction has rubbed a hole in the verandah roof then you will need to fit an under flashing as above but cut the main roof back so the under flashing will slide in.
Photos would help please if possible.

Originally Posted by rwbuild

Forget the 2 screen shots and the foam (goes hard and brittle after about 18 months).

Photos please but the chances are the verandah sheets were not "weathered" as Kryn has said. Also, you will probably find a build up of dust/leaves behind the lap of the main roof and the verandah if the main roof does not marry in tight with the verandah roof. If this is the case you need a custom flashing bent to the angle of the 2 roofs that is 73 deg with with 100mm under the main roof and min of 150mm with 20mm crush fold over the verandah roof. Use the small hex stitching screws to fix to the verandah roof, none needed on the main roof.
The other scenario is that the 2 roofs are tight fitting but expansion/contraction has rubbed a hole in the verandah roof then you will need to fit an under flashing as above but cut the main roof back so the under flashing will slide in.
Photos would help please if possible.

Thanks. We are having constant showery weather here at the moment. When the showers stop I will get up on the roof and take some photos.

Originally Posted by KBs PensNmore

Was the verandah roof put up by the previous owner or done professionally?? I would say that the verandah roof isn't folded on the ends in the valleys. This is done with a pair of pliers and the material in the valleys bent up at about 45 degrees. This is done to prevent your problem, if possible the sheets need to be removed and the ends folded up. The other thing that could be causing the problem is the nails have become loose, replace them with roofing screws, if that is the case.
If you do lift the sheets to fix the ends, instead of using tape, I'd put in a bituminous foam strip between the two surfaces.
Kryn

Kryn, the verandah is part of the original build. I believe the edges are turned up but will check when I lift the sheets. The builders did put a white foam-like strip under the join. The house is built on poles, on a 25 degree slope, and I think that some settling over the years may have added to the problem.

Hi
thinking about it, I suspect that the roof sheeting is "flooding" where water running down the 22 degree slope cascades onto the flatter veranda roof. If it were on a river, the problem would manifest itself as a "stopper".
You are noticing the problem more because the original "foam like strip" has deteriorated.

A full "solution" would require moving the discharge from the steeper part of the roof further down the veranda roof -- which is almost certainly not practical. Though a 450 mm wide flashing (in a compatible material) between the two roof profiles might work.
The next best option is to dam every valley in the veranda roof so that water coming off the steeper roof can't travel uphill on the veranda roof sheeting.

Originally Posted by rwbuild

Forget the 2 screen shots and the foam (goes hard and brittle after about 18 months).

Photos please but the chances are the verandah sheets were not "weathered" as Kryn has said. Also, you will probably find a build up of dust/leaves behind the lap of the main roof and the verandah if the main roof does not marry in tight with the verandah roof. If this is the case you need a custom flashing bent to the angle of the 2 roofs that is 73 deg with with 100mm under the main roof and min of 150mm with 20mm crush fold over the verandah roof. Use the small hex stitching screws to fix to the verandah roof, none needed on the main roof.
The other scenario is that the 2 roofs are tight fitting but expansion/contraction has rubbed a hole in the verandah roof then you will need to fit an under flashing as above but cut the main roof back so the under flashing will slide in.
Photos would help please if possible.

Today I took some photos which will make it clearer for you to understand the true scenario.


I also got my digital level and put it on the battens at every joist and quickly discovered that the verandah roof is virtually flat as it ranges in slope from 0.4 degrees to 1.5 degrees. So when there is a heavy shower the water does not get away and backs up and runs out the back of the upturned ends, then runs down the fascia and goes in between the fascia and the beam to which the joists are attached. On the top of the roof I pulled some sikaflex away and you can see the join. I am not sure how far the house roof sheets overlap the verandah ones, but I guess it is not very far at all.


I would like to fix this problem myself and fix it once and for all time. Unfortunately, I am not a plumber but have a good array of tools, snips, grinders and a pan brake and magnabend at work.


Appreciate your further comments.

Thanks for photos.
The only realistic solution is to remove verandah sheets and middle batten and batten closest to house, turn the house end batten on edge, use a straight edge from gutter batten to house batten, measure in middle, this will be the height of your middle batten.
Now get a verandah sheet and lay on top of the graded battens and where it intersects with the main roof is where you will cut the sheets so the verandah sheets slide under the main roof sheets. Be careful to locate the graded battens to coincide with the existing screw holes in verandah sheets. You may even have to put a new batten under the intersection of the verandah sheets and main roof.
You will also have to use all new roof screws as the old ones will have perished seals under them and more than likely the protective coating on the heads will be damaged and show signs of rust in a very short period of time after reusing, not worth the hassle.

Thanks for the pics, makes it easier to understand the situation. What should normally happen when an "extension" like this is done, a C section with bituminous foam is put in place where the sheeting meets the fascia, the sheets are then pushed in hard against the foam. The sheeting and C section are then sometimes pop riveted together, to secure it. Go to your local verandah supplier with a show area and have a look at a verandah that is attached to a building for ideas.
Kryn

corrugated roofing has a minimum angle of 5°, more in high rainfall areas. But if you follow rwbuild's suggestion of turning the batten on edge to increase the verandah roof pitch you move the intersection point further into the main roof, and I would strongly advise against any changes that shorten the main roof sheets. The verandah roof sheets would need to be longer also, because the increased pitch raises the height of the intersection point which also moves towards the ridge due to the 22° main roof pitch. Water leaking down the outside wall and behind the waling plate is an irritation but water leaking into the main roof cavity is a real problem. Turning the batten on edge is unlikely to get you up to 5° if you're at 1.5 now, so there is still the risk of water ingress.

I would normally retain the gutter on the main roof, and fit the waling plate below fascia level so the skillion roof is under the gutter or better still under the eaves if there's enough headroom. Or use box gutter and do a flyover skillion.

Look at the 4th photo, the sealant has failed and in some places actually will hold water BEHIND it

Originally Posted by Kidbee

I also got my digital level and put it on the battens at every joist and quickly discovered that the verandah roof is virtually flat as it ranges in slope from 0.4 degrees to 1.5 degrees.

I would like to fix this problem myself and fix it once and for all time. Unfortunately, I am not a plumber but have a good array of tools, snips, grinders and a pan brake and magnabend at work.

Appreciate your further comments.

unfortunately the roof on your veranda is too flat for the custom orb (corrugated) profile to work. A true permanent fix will include replacing the custom orb ovr the veranda with a profile better suited to a flat roof. Look up the Lysaght roofing manual http://www.lysaght.com/sites/default...ualJul2015.pdf for the profile that best fits the slope on your veranda.

I'd then be looking at a wide flashing between the 22 degree house roof and the nearly flat veranda sheeting to move the water insertion point further away from the main roof.

While I like the idea of also installing a box gutter, I wonder if you have the head room that sort of gutter would require.

Veranda pitch is way too flat. Water speed running down main roof is damed by slow water on veranda. Valley corrugations have been left without turn up. The whole thing has been reliant on a caulking seal between the two roof planes.
Even if the valley corrugations are turned up, there would still be a strong chance of overflow and there may not be enough sheet length to allow for the turn up under the main roof.
A simple fix would be to run a small gutter between the first batten and the whaling board and leave the veranda sheet corrugations as they are, without a turn up.

See attached Roof.pdf

If you opt for a different roof sheet profile, the min pitch will determine changes and require a custom transition flashing