Michael Tucker
Hello Andrew, It could be mortar or the flashing, I would suggest you set a budget of £250 The service in getting advice/survey is free and you should get 3 tradesmen to quote so you should use it. Tradesmen pay for the opportunity to quote on your job. It is important to give tradesmen contacting you the opportunity to do so, the advice you receive is free. You are not obliged to use any of them. Regards Michael