Single storey extension of two storey?

gimpotronitus

Hi,

I am planning an extension this year to my house. I had initially planned for a single storey extension to the rear to accompany the existing flat-roof single storey extension that is currently in place.

Now I am thinking that probably half the cost of getting a builder on site is, well, getting him and his gear and all that there in the first place (you know what I mean). So maybe getting a two story extension may not be *double* the price as it were...

The floor area for the new ground floor extension is 14' x 7'. The floor area for the second floor extension would be double that (since there is an existing single storey ground floor extension taking up the same space again).

Anyone have any experience with builders costs in this way?

thanks.

Victor

All very dependent on layout etc, but you will essentially have only twice the roof and much the same foundation. For getting 3 time the floor space, expect to pay maybe 2.5 times the cost.

However, this does not include the cost of fitting things out - add for bathrooms, kitchen and anything but basic finishes.

wideband

Now I am thinking that probably half the cost of getting a builder on site is, well, getting him and his gear and all that there in the first place (you know what I mean). So maybe getting a two story extension may not be *double* the price as it were...

Hi,
Just so we understand, you have an existing single storey extension which you are going to extent upwards to create say an additional bedroom and bathroom....too the rear you are also thinking of extending outwards for a larger kitchen/dinning area.

just a couple of thinks you might be able to tell us, did you build the existing extension or was it there when you bought the house and have you a side or rear entrance.

gimpotronitus

When I bought the house (a small 2up 2down redbrick) it already had a single storey, flat roof extension at the back containing a bathroom and an "extended" kitchen taking up approximately half the width of the house. I am definitely going to build a single story extension on the remaining half of the width of the house, if you know what I mean. I am just wondering with the builder on site etc.. would economies be realised by getting a bigger job done and go for a two storey extension while he is there?

wideband

ok, the way i see it is...if the foundations of the existing building allows for you to extend upwards and there is no existing sewers in the way...victor would be right 2.5 times the cost...as building the second storey is no cheaper even allowing for the fdns and slab and thats allowing for economies of scale as that type of work is tricky.

Allowing for (very) roughly the following -
removing the existing flat roof
making good the tops of the walls
joisting and boarding out for floors over
building upto wall plate level of main building on top of both new and old,
putting on a flat roof
breaking into your first and second floor main building,
inserting steel beams under wall plate of ex. roof...
possibly moving the existing bathroom upstairs

see ya

rooferPete

A lot will depend on the way the original extension was built, if in Dublin it may have had the foundations passed by the (now replaced) building bye laws inspector.

I would check that out because it could save you money, no Architect is going to sign off on a two story extension when he has no idea if the foundations are adequate.

It may be cheaper and better if the original extension is demolished and you have a clean start to finish job with no reason for anyone to hide behind "old exscuses" in the future.

While the size of the new building may not appear very big even the experts get surprises when the finishing costs start to mount up.

Set your budget and work within it, this could mean having a good single story extension built now with allowances for the propsed second level in the future.

Items like heavy roof joists, a parapet wall all round etc this would mean the second stage can start with minimum disturbance to the new extension.

Best of luck for the new year.

wideband

hi,

very good idea that is rooferPete !!