Extending a house...

[Unbelievable Jeff]

So we're looking at putting a small one storey extension on our house to increase the size of our kitchen. It will be 16' x 9' 6", and need a pitched roof with a couple of skylights. We will however only need one of the 16 ' and one of the 9' 6" walls built (we are putting in bi folding doors for one of the 9' walls, and the other 16' is adjoining the kitchen and so will be open.

 

Does anyone know how much we'd be looking at for the digging of foundations, 2 x walls and roof (I can do the rest)? Also, will we need planning permission for it? I believe rules have been relaxed relatively recently.

 

Cheers,

 

Jeff

[Chopper71]

Might not be 100% correct, but you would only need planning permission if the extention is visible from the front or if you are going to within 1 metre of the boundary. In terms of cost I wouldn't expect it to be huge. We built a 21' by 9' extention with 15' bi-folds and the cost (including all the plastering, running of electrics, windows) was about £25k.

[Unbelievable Jeff]

Might not be 100% correct, but you would only need planning permission if the extention is visible from the front or if you are going to within 1 metre of the boundary. In terms of cost I wouldn't expect it to be huge. We built a 21' by 9' extention with 15' bi-folds and the cost (including all the plastering, running of electrics, windows) was about £25k.

 

Certainly the electrics, plastering, flooring etc I can do myself, so that would cut the cost down a lot more. The house is semi detached, and the extension would be going within 1m of the boundary, so it sounds like I will need planning for it...

[bridge too far]

This might be handy

 

http://www.homebuilding.co.uk/advice/costs/calculator

 

If you do need planning permission (and maybe even if you don't) you'll need Building Regs approval. Unless you are a qualified tradesman, I don't think they would allow the work if you are undertaking a lot of the trades yourself.

[Unbelievable Jeff]

This might be handy

 

http://www.homebuilding.co.uk/advice/costs/calculator

 

If you do need planning permission (and maybe even if you don't) you'll need Building Regs approval. Unless you are a qualified tradesman, I don't think they would allow the work if you are undertaking a lot of the trades yourself.

 

Yep, fine with building regs approval as can get my work signed off by qualified tradesman, it's something I have done for other parts of the house already.

 

Will have a look at that site.

[bridge too far]

The rule of thumb used to be about £1K per sq. metre but I think that's basic. Bifold doors, underfloor heating - all those nice extras would add to the bill I guess. But if you're doing a lot of the stuff yourself that would offset the little luxuries.

[Unbelievable Jeff]

The rule of thumb used to be about £1K per sq. metre but I think that's basic. Bifold doors, underfloor heating - all those nice extras would add to the bill I guess. But if you're doing a lot of the stuff yourself that would offset the little luxuries.

 

That's it, in essence I only need foundations digging, 2 x walls building and the roof being built. It's only these parts I need the costing for as I can cost the other stuff quite easily as I already have a lot of the other stuff that I need!!

[Tony F]

Of course you'll need to have your drawings approved by a structural engineer and he'll probably insist on hugely oversized girders being inserted to ensure that it can withstand an 8.9 earthquake (in other words it will end up being hugely over-specified in my experience). Building Regs will then want to see the structural requirements incorporated.

[Unbelievable Jeff]

Of course you'll need to have your drawings approved by a structural engineer and he'll probably insist on hugely oversized girders being inserted to ensure that it can withstand an 8.9 earthquake (in other words it will end up being hugely over-specified in my experience). Building Regs will then want to see the structural requirements incorporated.

 

I will have an architect do the drawings for us. We will certainly need at least one large RSJ putting in, around 12 feet I reckon.

[Dimond Geezer]

Your Architect will advise whether you need Planning approval (from what you describe, you may not as this may fall within your permitted building rights it'll depend on the relationship between the size of your existing property the new build). You'll will almost certainly need Building Reg approval, again your Architect will advise. What you've described sounds fairly straight forward & a more economic route would be to use an Engineer rather than an Architect. There are plenty of Engineers who can advise on the above & produce drawings to satisfy planning & Building Control doing the job a lots cheaper than an Architect/Engineer combo.

If you need any further info pm me as I know just the chap for you.

[Dimond Geezer]

This might be handy

 

http://www.homebuilding.co.uk/advice/costs/calculator

 

If you do need planning permission (and maybe even if you don't) you'll need Building Regs approval. Unless you are a qualified tradesman, I don't think they would allow the work if you are undertaking a lot of the trades yourself.

 

The work will need to be sanctioned & inspected by Building Control (Building Regs) whether the tradesman is qualified or not, the exception being Electrics & replacement windows.

[egg]

Nobody can you give you price without seeing the site, and preferably the drawings. We could be looking at 1m footings, or 2m. We could be going into clay. What's the new pitched roof being tied to? What's the score with drains?

 

Get a builder round and let him price.

[Unbelievable Jeff]

Your Architect will advise whether you need Planning approval (from what you describe, you may not as this may fall within your permitted building rights it'll depend on the relationship between the size of your existing property the new build). You'll will almost certainly need Building Reg approval, again your Architect will advise. What you've described sounds fairly straight forward & a more economic route would be to use an Engineer rather than an Architect. There are plenty of Engineers who can advise on the above & produce drawings to satisfy planning & Building Control doing the job a lots cheaper than an Architect/Engineer combo.

If you need any further info pm me as I know just the chap for you.

 

Excellent, thanks for that DG, I may well take you up on that. I'll let you know.

[Doctoroncall]

Also depends on if you are in conservation area for planning approval. Your architect will be able to estimate the cost.

 

For beams you can use this... http://www.beamcalculation.co.uk/

[Dimond Geezer]

 

For beams you can use this... http://www.beamcalculation.co.uk/

 

I'd be a bit careful with that, the example I looked (No. 19) seems to assume that no load is attracted from the roof, and assumes non-load bearing studwork at first floor, yet calls up a masonry wall.

[Tony F]

I will have an architect do the drawings for us. We will certainly need at least one large RSJ putting in, around 12 feet I reckon.

 

Point I wanted to make is that regardless of who produces the drawings you need a structural engineer to sign them off as structurally sound. An architect can in theory design you a house that won't stay up.

 

You'll need to pay the engineer - if you use an architect too, you'll need to pay both. I make this observation cos it caught me by surprise - it was only after after I'd paid a lot of money to an architect to turn my sketch into proper drawings that I found out that it was an absolute obligation to then get a structural engineer's say so, He added in more beams and the cost of the project sent up as well as me having to pay his fees. Building Regs then enforced the structural engineer's design (not the architect's) as well as all the other Building Regs stuff like insulation - oh yes LOTS of insulation!!

 

Hence my comment / advice.

[egg]

Point I wanted to make is that regardless of who produces the drawings you need a structural engineer to sign them off as structurally sound. An architect can in theory design you a house that won't stay up.

 

You'll need to pay the engineer - if you use an architect too, you'll need to pay both. I make this observation cos it caught me by surprise - it was only after after I'd paid a lot of money to an architect to turn my sketch into proper drawings that I found out that it was an absolute obligation to then get a structural engineer's say so, He added in more beams and the cost of the project sent up as well as me having to pay his fees. Building Regs then enforced the structural engineer's design (not the architect's) as well as all the other Building Regs stuff like insulation - oh yes LOTS of insulation!!

 

Hence my comment / advice.

 

There's no obligation to get a structural engineer on any job.

 

He will need building control to pass the job. In doing that and/or getting consent he will need to submit full details of the job. If a steel is needed then he'll need to submit calculations. An engineer need not do that and many competent architects/planners and even some builders will do steel calcs.

 

I've submitted my own calcs (done with assistance) and building control then did their own checks to satisfy themselves.

 

On insulation, yes there's a lot needed but a "u" rating isn't that difficult to calculate and again many competent architects/planners/builders can do them if you can't do it yourself.

 

There really isn't a need to use an architec and structural engineer on any domestic building job of this size - the right person will be able to do it all.

[Special K]

Just doing my own extension of a similar nature by the sounds of it. Expect to pay between 20k and 30k depending on Kitchen selection. From my experience i can offer the followig advice if you want;

 

Go for a pre-app planning meeting at the Councils place in Guildhall sq. You meet a planner who can advise, FOC, if you need PP. I paid them 30 quid for a confirmation letter that mine was within PD rights (for later if selling). General advice can be found on the Planning Portal website - http://www.planningportal.gov.uk

Consider party wall agreements with neighbours if digging within 3m of their foundations. - Can take a long time.

Get a Structural Engineer to do your structural calcs. Generally cheaper than an Architect. You'll need them for Bldg reg approval and unless you've got loads of time, leave that up to the experts. I know a very good Engineer if you want.

Consider private building control companies for B Reg approval - you dont have to go with Local Authority.

Generally foundations will be dug and the Inspector will confirm the depth dependant upon the ground conditions.

Try for an account at the local builders merchants if you are doing it yourself - although B&Q trade card prices are OK.

Websites like Celotex or Kingspan will offer you approx u Value calcs for floors, walls and roofs. If you are going flat or shallow pitch, go for a warm roof.

Shop around. Specialists like SIG will be better on insulation than Travis Perkins for instance.

Thermalite blocks are on a horrendous lead in at the moment - 10- 12 weeks generally and this is likely to last well into next year, so be aware of this. roof tiles will be next as housebuilding picks up and soaks up all available materials.

 

HTH.

[Dimond Geezer]

Special K gives some good advice here, the Party Wall Agreement is something I forgot to mention, although it shouldn't necessarily take very long, keep yout neighbours on side & informed & it could all be done with an exchange of letters. Everything you need is here, including proforma letters:

 

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/207310/Party_Wall_etc._Act_1996_-_Explanatory_Booklet.pdf

[Viking Warrior]

Excellent thread Jeff

 

I'm contemplating putting an extension on my house to. . Down below a garage and utility room joined on to the kitchen and an extended bedroom with a conservatory type room above the garage . Anyone done something similar to their houses I have a one and a half storie house

[derry]

Excellent thread Jeff

 

I'm contemplating putting an extension on my house to. . Down below a garage and utility room joined on to the kitchen and an extended bedroom with a conservatory type room above the garage . Anyone done something similar to their houses I have a one and a half storie house

 

I bet it will have triple glazing and lots of insulation:lol:.

[Viking Warrior]

Very good Derry

 

The roof tiles are nailed in

 

Dont have triple glazing . more quadruple owing to the thickness of the glass they use here

 

If it is really windy up here the windows do occassionally go a strange shape. Im expecting an implosion at any time

[tpbury]

Conveyancer for our UK house sale wanted regs approval for dormer done in 1977, or else indemity insurance. Same story for rsj we put in in 2005 - didn't question the builder at the time, but the conveyancer is wanting indemnity insurance for that work as well. Apparently, no building indemnity claim has ever been made. Bar tards

[bridge too far]

Conveyancer for our UK house sale wanted regs approval for dormer done in 1977, or else indemity insurance. Same story for rsj we put in in 2005 - didn't question the builder at the time, but the conveyancer is wanting indemnity insurance for that work as well. Apparently, no building indemnity claim has ever been made. Bar tards

 

They want certificates for everything these days. This time last year we sold our house. We'd had a new kitchen installed 18 months earlier and they wanted sight of gas and electricity certificates as well as the guarantee for the kitchen itself. I think also the rules have just changed in that sellers are obliged to notify potential purchasers of problems such as, for example, difficult neighbours, problems with drains etc. etc. whereas before it was Caveat Emptor

[Tony F]

There really isn't a need to use an architec and structural engineer on any domestic building job of this size - the right person will be able to do it all.

 

I agree the key is knowing you have the right person.

 

In my case I paid for an architect, who spent loads of time and (my) money producing the drawings - but I only later found out that he had no intention of doing the structural calculations. Hence why I then had to get a structural engineer to do them.

 

Thats the warning I am flagging up to the OP

[bridge too far]

Look what I've just found whilst looking for something else

 

http://www.labc.uk.com/technical-faqs

 

Might be helpful?