What specialist

[AndrewFitton]

I actually built my house 9 years ago. After living with it I have one gripe which is the utility room and en suite are not big enough. No problem as the house is essentially a box with a small single story “lean too” box built in block and sip and if I take down the lean too box and put up a two story box a metre wider two metres longer the job is a goodun. The bit that I bother on about is the whole house is on a beam and block floor with under floor heating although the underfloor heating in the Lean too does not need extending as it’s almost too efficient already but can you extend beam and block on to new foundations - feels like you should be able to. 
 

The main question though is I could do with some really good engineering drawings put together and priced up. We didn’t have an architect first time round as this is a kit house that came with extensive plans. This extension is hardly going to trouble the creative juices of an architect but strictly the new box has got to work as well as the rest of it ( which works really well). Would you use an architect, a building a surveyor or a suitable buildings engineer for this?

[Gus Potter]

56 minutes ago, AndrewFitton said:

I actually built my house 9 years ago. After living with it I have one gripe which is the utility room and en suite are not big enough. No problem as the house is essentially a box with a small single story “lean too” box built in block and sip and if I take down the lean too box and put up a two story box a metre wider two metres longer the job is a goodun. The bit that I bother on about is the whole house is on a beam and block floor with under floor heating although the underfloor heating in the Lean too does not need extending as it’s almost too efficient already but can you extend beam and block on to new foundations - feels like you should be able to. 
 

The main question though is I could do with some really good engineering drawings put together and priced up. We didn’t have an architect first time round as this is a kit house that came with extensive plans. This extension is hardly going to trouble the creative juices of an architect but strictly the new box has got to work as well as the rest of it ( which works really well). Would you use an architect, a building a surveyor or a suitable buildings engineer for this?

 

The simple way, as you'll be needing a decent found for the two storey extension is to cast a small strip of found to extend the existing house found assuming it is strip found you have and not ground beams on piles say. Other things to just be wary of is things like ground gas.. does your house have measures to contend with this and the like?

 

You can dowel this into the existing so long (good practice at least) as it appears to be just supporting the ground floor load. The foundation extension supports the new beam and block floor which can cantilever by up to say 75% of the beam depth to be safe if carrying a domestic floor load only.

 

If you know what you want then find an SE who also knows a bit about design (they will give you free tips) and getting stuff through building regs. They do exist! A good experienced SE will have spent many years working with Architects, good experienced Architects have spent many years working with SE's... it's a two way street! In other words a good Architect can size up stuff structurally and not often be wrong! it's just that doing calcs for BC is not often their thing!

 

Both if experienced will be well versed in how to do energy perfomance calcs, drainage design etc. Same applies to Building Surveyors, there are a few that are well rounded.

 

I would shop about if you know what you want then you may be best with the SE / Surveyor route as you'll maybe get more "construction" information?

 

 

 

 

 

Edited September 30, 2021 by Gus Potter
left hand

[AndrewFitton]

Thanks good thoughts here. 
 

Yes strip foundations. No ground gas. The only thing we have is very very heavy clay but the original main contractor put stupendous amounts of hardcore to about three feet deep and it’s compressed the clay to dry putty 20ft round the house and stops heave. The only problem is digging a trench in the hardcore is a special job as even a digger will just scrape it but I’d rather have it than not. 
 

Id use the same main contractor again but they are always busy and this will be a tiny job for them. I’ll ask them which engineer they would use. 

Edited October 1, 2021 by AndrewFitton
Added info

[joe90]

I don’t see why you need an SE, if you want drawings find an architectural technician, they are usually cheaper, their main job is drawings and will have dealt with construction details, IF building control want structural calcs THEN find an SE. If you want advice about your construction post it up here where plenty of us have knowledge to share. I designed our build and did not use an SE.

[AndrewFitton]

It’s a very heavy clay site on a hillside in one of the wettest parts of the U.K.  - construction round here can be challenging unless it’s done just so. There is a small estate up the way which is 30 years old that has very worrying looking cracks all over the (big) retaining walls. The main contractor was superb in getting the groundwork’s right here last time, and building control said they were excellent but I’m not sure I’ll get them for this. I feel comfortable with the idea of a chartered engineer now it’s been floated but I will go and see the builders who I worked with to build this and see what they think too - and whether they would act as main contractor again. 

Edited October 2, 2021 by AndrewFitton

[Mr Punter]

Yes, the builders who you had originally are definitely your best bet even if you have to wait a bit or pay a bit more.