I am about to embark on building a small extension, of size 1.5m x 3.5m, sited on an existing concrete driveway. I've never done foundations before, and have heard that it is very hard work, so I wondered about getting someone in to dig and fill the foundations, and install a new rainwater gulley. I've had three quotes, £2100 (but only as part of a build-the-entire-extension quote which I didn't want), £2700, and £2900 (all inc VAT). They're roughly comparable so I guess they are probably fair prices, but they are higher than I'd anticipated when I first did the costings for the extension a year or so ago. Have prices gone up a lot recently?
To keep costs down, I am thinking about doing it myself, but I'm trying to work out whether it is worth the hassle. I think I've got the rough idea of what needs to be done, but a few questions arise:
- If I cut out the perimeter with a concrete saw, are gas/water services deep enough to avoid being cut, or must I locate them precisely first? I know where they are already to about +/- 30cm. - I will use a powered breaker to smash up the concrete in the centre, taking care to avoid damaging the services. Is a mini/micro-digger useful, or more hassle than its worth for a small site? Maybe a self- propelled skip loader is a useful compromise? - Will the BC surveyor want to see a test hole already dug right down to 1m, or will they hang around and watch a test hole being dug until they're happy it's deep enough? - If I bought in ready-mixed concrete, will the operators level it out for me, or would that be my job? - Any other tips, or recommendations for making the job easier?
I'm sure other questions will arise as I think about this more :-)
, but are the savings really worth the effort?