Extension idea - Likely Cost/problems

[Ljc1980]

Due to growing family, we are considering a wrap around extension to our 3 bed semi to make it a 4 bed with larger kitchen and downstairs toilet.

I understand the first stage is to get drawings then quotes but thought I would ask for a likely cost on here before doing so as if it is prohibitively expensive we may move and don't want to waste architect fees.

Below are pics of current floor layout and proposed that I have done myself, as well as pics of rear of house. Is this enough to get a rough idea of cost?

Is there anything that strikes anyone as a problem with this idea? Does all the drainage going into the ground where the extension would sit cause a problem or add cost?

 

[pilsbury]

£1k - £1.5k per Sqm of floor area is the usual guide that is given. Down south tends to be dearer than up north.

 

[^woody^]

Looks like a massive drop on the neighbour's side, so that's very deep foundations there. If the drains are deep, then you'll need to dig down and bridge them too - and get permisson if public owned. So extra cost to the m2 cost.

Plus cost of steel work to hold the corner.

But will you get another house with the same additional volume that an extension will give, at the same additional cost? Probably not.

 

[Aeron Rees]

Just to point out as well that you wouldn’t get that under permitted developments so would have to submit a full householder application. Therefore your neighbours would be given the opportunity to comment on the application so it’s worth letting them know of any proposal in advance.

You would also have to consider the Party Wall Act.

Out of curiosity why have you got two walls between the new bedroom and living room sofa area?

 

[tomfe]

I would consider the use of a designer who can get the most out of that space.

 

[Ljc1980]

Thank so for you replies guys.

Aeron I just put that extra wall there so you wouldn't be coming straight out of a bedroom into a living area, and could have been a space for an extra bit of storage which the house lacks.

As tomfe said I would get a proper designer if I go ahead, I was just hoping my quick doodle would be enough to get an idea of cost.

Regarding PD, can you not extend out of the rear by 3m without full planning? That's all this design does.

As you can tell by the pics of the house, the current upstairs toilet waste runs where the extension would go, would this all be rerouted around the extension or be boxed in and flow through it, as I'm not sure I like that idea!

 

[Aeron Rees]

Hello

Your drawings show you extending to the rear and side of the original dwelling house. As you are extending to the side of the house, the extension cannot be any greater than half the witdth of the original dwelling house. Total width of extension, which it would be. Not permitted development.

 

[Aeron Rees]

Boxed in is easier, they are not actually that intrusive if done properly.