Extension costs

Play_fair84

Hello, 

interested in purchasing a property but would require a 2 storey extension to side as per attached plans (rough idea of extension drawn in pencil) . Property has good side access and is 1930’s. Any comments on rough cost please? We are in Lincolnshire, also any comments on design and potential difficulties or improvements welcome too!

Play_fair84

I should add that in these plans extension is approx 5.79 meters long by 3.6 wide downstairs and same foot print upstairs but potentially slightly wider at back to allow  for ensuite .

TELLIT01

When this question has been asked before the rough guide tends to be £2.5k to £3k per square metre for a single storey extension.  Presumably roughly double that for 2 storey.  That is basically for the shell, not fitting out.

ritz55

If it helps, we are doing a double story, rear extension and loft conversion. Total cost with underfloor heating and Air con, we are looking at around £350k in total. Contractor is asking £210k for the extension and anything we don't see included, this also includes the boiler, heating, plumbing, electrics etc. Anything we see such as tiles, doors, light switches final coat of paint, kitchen etc is on us, also Aircon is on us.  

casper_gutman

TELLIT01 said:

When this question has been asked before the rough guide tends to be £2.5k to £3k per square metre for a single storey extension.  Presumably roughly double that for 2 storey.  That is basically for the shell, not fitting out.

It should be less than double for a single storey, on average. Yes you need more bricks, but there's still only one set of foundations and one roof.

SadieO

casper_gutman said:

TELLIT01 said:

When this question has been asked before the rough guide tends to be £2.5k to £3k per square metre for a single storey extension.  Presumably roughly double that for 2 storey.  That is basically for the shell, not fitting out.

It should be less than double for a single storey, on average. Yes you need more bricks, but there's still only one set of foundations and one roof.

Don't you have to build stronger foundations though? And a more complicated roof given that it will presumably have to attach to the existing one? (Genuine questions, I don't know if you do or not!)

FreeBear

SadieO said:

casper_gutman said:

TELLIT01 said:

When this question has been asked before the rough guide tends to be £2.5k to £3k per square metre for a single storey extension.  Presumably roughly double that for 2 storey.  That is basically for the shell, not fitting out.

It should be less than double for a single storey, on average. Yes you need more bricks, but there's still only one set of foundations and one roof.

Don't you have to build stronger foundations though? And a more complicated roof given that it will presumably have to attach to the existing one? (Genuine questions, I don't know if you do or not!)

A little wider, a little deeper - The bulk of the cost is digging out the trench. At the roof line, it can get expensive if there is a complex set of rafters that need installing. A possibility of a crane being needed would add even more on to the bill.

Albermarle

ritz55 said:

If it helps, we are doing a double story, rear extension and loft conversion. Total cost with underfloor heating and Air con, we are looking at around £350k in total. Contractor is asking £210k for the extension and anything we don't see included, this also includes the boiler, heating, plumbing, electrics etc. Anything we see such as tiles, doors, light switches final coat of paint, kitchen etc is on us, also Aircon is on us.  

I am guessing that the size of your double extension is a bit bigger than the OP's which is approx 21 m2 on each floor ?

Play_fair84

ritz55 said:

If it helps, we are doing a double story, rear extension and loft conversion. Total cost with underfloor heating and Air con, we are looking at around £350k in total. Contractor is asking £210k for the extension and anything we don't see included, this also includes the boiler, heating, plumbing, electrics etc. Anything we see such as tiles, doors, light switches final coat of paint, kitchen etc is on us, also Aircon is on us.  

350k!! Oh my goodness, are you in London/SE? Think we’ll have to forget this if this is representative…how many square meters is your build?

Cinders:

How do you get out of the master bedroom? Isn't there a big drop to the stairs, or have I missed something on the plans?

ritz55

Play_fair84 said:

ritz55 said:

If it helps, we are doing a double story, rear extension and loft conversion. Total cost with underfloor heating and Air con, we are looking at around £350k in total. Contractor is asking £210k for the extension and anything we don't see included, this also includes the boiler, heating, plumbing, electrics etc. Anything we see such as tiles, doors, light switches final coat of paint, kitchen etc is on us, also Aircon is on us.  

350k!! Oh my goodness, are you in London/SE? Think we’ll have to forget this if this is representative…how many square meters is your build?

Yes, we are based in North London. Total extra floor area is just over 100m2