If you have a flat corrugated iron roof and it is leaking here are some of the things you should check.
- Get up on the roof and look for holes opposite the areas in which the leaks are seen.
- If there are holes these could be from two causes. Either the roof is very old and has rusted through or holes have been made and have not been filled, for some reason.
- The flashing details at the top edge of the roof where it butts up against a parapet wall or sill may be leaking.
- Where roof-sheets overlap, check that the sheets are seated flush or close to each other and are not gaping. The roof sheets should have been laid with the overlap against the prevailing North-Westerly winter rainfall winds.
In the event of holes in the roof a three part repair is recommended here.
- Seal all the relatively small holes with a polyurethane sealant.
- Apply a fully saturated semi-flexible polypropylene membrane over the damaged areas. Allow to cure.
- Overcoat this work with an appropriate roof waterproofing paint.
If the roof sheets are rusted through they may not be able to be saved, in which case they may have to be replaced.
Please refer to the writer for further advice in this regard.
Flashing details should be inspected and repaired where de-lamination has occurred.
Overlaps should be checked and ‘gaping’ seems (overlaps) repaired appropriately. Also direction of lay inspected relative to house orientation and weather patterns.
I any event, when inspecting the roof, care should be taken where one places ones feet. Some roof sheets are very thin, that in combination with inappropriate spacing for support rafters could result in its failure and damage of the roof sheets.