How to go about extending with 1800's foundations.

[Biglad]

Hi all.

 

New to the site, I've joined for advise on extending my house.  

 

I have an old farmhouse in the Cambridgeshire fens I am looking to extend with a single story, plus some internal work.  I have a little building experience having extended my previous (1970's) house... but this was on significantly different foundations, and my experience in the trade was working for a building firm on new build - so I have never worked with this kind of foundation..

 

My house was built circa 1850 and I dug a very small test pit over the weekend, to get an idea of what lies beneath... I've attempted to upload a pic.

 

So on first inspection there appears to be approx 450mm footing, with courses 1 & 2 stepped, then a further 3 - 4 courses rising to ground level.... course 1 appears to be laid directly over clay.

 

So the building is approx. 170yrs old and the area is known for subsidence, its a two story 4 bed house, regular structure with a load bearing wall off-centre, rising through both floors, parallel with the roof ridge.  I had a full structural survey done during conveyancing and the surveyor identified their had been movement in the back of the building some time ago, but there were no signs of it having moved recently.

 

There are two elements to the building work I would like to do and that is a single story extension (living room) perpendicular to the gable end, and knocking through the load bearing wall to make what is currently the living room/kitchen... into one large kitchen diner.  This would require an RSJ and I would imaging excavation for additional footing where the load of the RSJ transfers.

 

Looking for some advise on how to go about this.  If it weren't for the footings I would dive right in, but naturally I'm complacent given what I have.  Should I bite the bullet and pay someone to take on the whole project (along with its risks)... or can this still be approached with separate trades, plus project management and additional bits done myself.

 

Anyone with experience of similar situation?  Any advise appreciated. ?

[Mr Punter]

Hi @Biglad and welcome.

 

Not sure if you need planning consent or if this would be covered by permitted development but you would need building regs in any case and I suggest you get plans drawn up with calcs and bearing details for the steels and submit these to building control and you can ask for their comments on foundation type as they should be familiar with what is required where you are.

 

You could get a builder to do the shell and finish it yourself.  There should not be too many risks with this type of project.