I'm not sure that I understand the nature of this thread. Is is a 'quiz', to which Glyn1959 (who has not returned since the OP) knows the answer (what caused it?), or is he actually looking for suggestions as to the cause (which he doesn't know)?
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local