Is my architect talking rubbish?? Builders view needed :-)

[scotster]

OK, first lets set the scene..

I have an existing single story side extension of single brick skin around 2m wide running down the side of the house which is around 11m.

It has a corrugated roof on and serves as an 'out house' for bikes etc and it is accessed from the behind the house via a single door.

I am putting a second story on top of it and and knocking through downstairs and up stairs rooms adjacent to basically push the whole side of the house out by 2m.

When I first had builders around to look at this they said I would need to demolish the existing single story extension, and re-do all the footings to take the weight of the double story.

Fair - enough, thats what I thought too.

My architect has said that in fact I can simply underpin the footings in three or four places (eg two corners and the centre) put in steel uprights on those three places just inside the external wall.

Then I span the uprights with RSJ's running at ceiling level and abutting the external wall. I then build the upper floor on top of this steel. I block or board out the lower level to building reg standards and Bobs your uncle... no demolition or new footings required. He says it will be much, much cheaper even with the steel

When I challenged him on wether a builder would have experience of doing this and how 'do-able' it was he said that it was often done in the case where people over build on the top of garages.

Thats seemed like a sensible answer!!

Can anyone advise me on if this is a fairly standard approach that most builders will happily take on or is it going to cause me grief...

All comments welcome!!

Regards, Scott.

 

[^woody^]

The Architects solution is valid and common.

The issue is whether the costs, time and trouble favours one method over the other.

 

[Shytalkz]

Absolutely fine approach. Unusually sensible for an architect, as well

 

[noseall]

i would demolish the lot and bury the rubble in a soakaway.

anyone who has had hands on experience of underpinning will know where i'm coming from.

hire a micro digger, hoof out the existing foundations and dig a proper one.

pratting around with steel and underpinning seems like a lot of fuss for a lesser job.

 

[scotster]

Very good range of responses!!!

Disagreement, agreement and the 'pros and cons' response!!

Ill take the advice on balance then and sound out some of my short list of builders nearer the time.

Cheers.

 

[Shytalkz]

pratting around with steel and underpinning seems like a lot of fuss for a lesser job.

Ah, but rebuilding will result in a cavity wall and a loss of floor area in the downstairs area.

Depends what the OP wants: to maintain the space as is - apart from at the post positions - then upin is viable. If not bothered about losing approx 8" off the width and 16" off the length, knock down and rebuild.

 

[noseall]

shy, the two jobs do not compare.

one is unfeasible the other is logical.

there will be no time save. there will be no material cost difference.

space save yes, but a worthy sacrifice for peace at night.

 

[scotster]

Is there a consensus that there will be no materials and labour saving even though new gorund works would have to be done?

That is my main selection citeria!

Cheers.

 

[Shytalkz]

Sorry Nose, you and I don't often diverge , but...

It wouldn't require underpin all along the length of the wall, all it will need is pad bases for the posts and even these could be eccentric to avoid going under the ex founds, unless they're very shallow and/or on **** ground.

I wasn't coming at it from any time/cost save pov, but purely on the basis that the OP would want to retain the entire internal area of the existing footprint. I would assume that that is what he said to his designer, for him to have made that suggestion.

 

[scotster]

Hi Folks.

Just to be clear - the wall is currently a single brick thick. The area will be a internal rooms - the back half becomes part of the kitchen and front a downstairs toilet so it will need boarding up with enough insulation for standards. Im not sure how that s achieved and how much space it looses and space isnt a big worry.

I didnt particular ask for the space saving. The architect said it would be cheaper...

Would you argue with that?

Rgds, Scott

 

[Shytalkz]

Ah right. No, I wouldn't agree that it would be any cheaper and if you're intending to use downstairs as a habitable area, a knock down and rebuild will give you a better job all in all.

 

[scotster]

Thanks Gents!

I now know to 'proceed with caution'

Scott.