First time getting house extension

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Fist time getting house extension and looking for some help from those who have been through the same process.

Nothing major, will be rear ground floor extension. Main reason is to extend our living space as we both work from home now due to covid and we are expecting out second child so would be nice to have some play space for the kids.

We have found good company who will be doing the extension (did extension few doors down from us and they did great job), they require drawing so they can give us a quote. Now this is a point where i need help please. We decided we are going to remortgage to pay for the work. Regarding the drawing is it worth going to an architect or go with structural engineer ? Also do we get drawings first, go to build company for quote and than go to mortgage company ? Or should we speak to mortgage company first and get out budget sorted before we go to architect/engineer so they know what we got to work with ?

Any input would be greatly appreciated from those who have experienced the process :)
 
Soldato
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Drawings
Cost of works
Remortgage
Instruct builder with commencement date and contractural obligations

cry.
 
Soldato
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  1. go first to architect (could ask your neighbour for reccomendations?)
  2. get structural engineer calculations (could put this later and builders will have to give TBC estimates on steelwork
  3. >Get builder cost
  4. remortgage
  5. instruct builder

Is how I would do it I think (I'm lucky in that I've never had to remortgage to fund house modifcations, but would presume it'd be best to after you have the price to ensure you can afford it/go ahead.

If you want a rough estimate I've read online use £3k for every square metre you're adding (prices are crazy atm!) e.g. 3*5 = 15 square metres
*3 = £45,000
 
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  1. go first to architect (could ask your neighbour for reccomendations?)
  2. get structural engineer calculations (could put this later and builders will have to give TBC estimates on steelwork
  3. >Get builder cost
  4. remortgage
  5. instruct builder
Is how I would do it I think (I'm lucky in that I've never had to remortgage to fund house modifcations, but would presume it'd be best to after you have the price to ensure you can afford it/go ahead.

If you want a rough estimate I've read online use £3k for every square metre you're adding (prices are crazy atm!) e.g. 3*5 = 15 square metres
*3 = £45,000
Builder has recommended architect local to us so will speak to them and see what they say.
Our house value has shot through the roof in seven years we have lived here so best for us would be to remortgage.....we have saving but I have two elderly parents overseas so rather have that money just in case.
Regarding price per square meter, I agree about it being crazy .....from what I understand it's price of materials that's shot through the roof. We are aiming for small 12 square meter extension and builder said we should aim to max budget £40k.

Thanks for the help @Buffman and you too @fastwunz :cool:
 
Soldato
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If you've already spoke to the builder and have confidence in them then I guess you have a flavour of additional cost - main thing will be specification after that (e.g. if flat room, warm roof EPDM, triple glazed roof lanters, bifold doors, etc.).. Id say over budget for cost at this stage.

Yes a lot of it is materials but also labour costs have gone up - competitive market so buiders can go to the highest builder

Will your builder be managing all your subcontractors e.g. electrics, plumbing, plastering? If you're a little unsure on the process it might help you having an outfit that "does it all"
 
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If you've already spoke to the builder and have confidence in them then I guess you have a flavour of additional cost - main thing will be specification after that (e.g. if flat room, warm roof EPDM, triple glazed roof lanters, bifold doors, etc.).. Id say over budget for cost at this stage.

Yes a lot of it is materials but also labour costs have gone up - competitive market so buiders can go to the highest builder

Will your builder be managing all your subcontractors e.g. electrics, plumbing, plastering? If you're a little unsure on the process it might help you having an outfit that "does it all"

Yeap will take all of that into account, he said they are good to work with the budget and see where we can save if needed.
It doesn't help that we are outer London which drives prices up even more.
His company does everything, think his team had 8 people so they cover all the trades. Will obviously go over everything with the builder before we go ahead with anything, will also speak to the neighbour and see how their process with the company was.

All this is new to me so your help is greatly appreciated !
 
Soldato
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We built a single story rear 4x3 extension earlier this year. I drew plans myself, got a quote from a recommended builder, filled in the building control applications (permitted development), then he built it. It came to a little over £20k, including skylight, vaulted ceiling, windows, bifold doors, internal doors, plumbing, electrics, flooring etc... Oh, and retaining wall in the garden.

I just had to paint the walls and woodwork.

Im "up north" so not sure if it's regional, but some of the prices I see quoted on here seem crazy to me!
 
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Prices here around London are absolutely crazy if you want any kind of work done. Company we are planning to go for are mid priced, could find cheaper if we really looked but they have really good reputation.

You definitely got yourself a good deal :D
 
Soldato
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Get a full technical drawing done by a professional before you start. This is the only way to accurately cost a build and shouldn’t result in any surprises.

DO NOT RUSH.

You’re lucky that you have a good builder on hand, but definitely get some other quotes.
 

Jez

Jez

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We built a single story rear 4x3 extension earlier this year. I drew plans myself, got a quote from a recommended builder, filled in the building control applications (permitted development), then he built it. It came to a little over £20k, including skylight, vaulted ceiling, windows, bifold doors, internal doors, plumbing, electrics, flooring etc... Oh, and retaining wall in the garden.

I just had to paint the walls and woodwork.

Im "up north" so not sure if it's regional, but some of the prices I see quoted on here seem crazy to me!
My experience is the same as yours (although have required planning each time) Ive done lots of building work like this, i have always drawn all plans myself (planning has never had an issue with any of my drawings, it isnt hard, you submit them to the pre planning advice officer first anyway) - and then served a building notice to the LABC for building regs approval, you dont need any technical drawings at all for domestic, bar any local specifics such as calculations for complicated steels - these can be sandboxed to illustrate just that one element though if required - they'll inspect as you go and as often as you like.

Ive done 2* 2 storey extensions, a single storey extension, and a garage conversion (2 storey) this way. A total of around 150sqm in additions. Never cost anything even close to the prices quoted here. Break everything down, one contractor for groundworks, let them clear off, get it inspected, pay them, hire a bricklayer, get the walls done, get another inspection, pay them, hire a chippy, get the roof structure done, inspect, pay them, get a roofer in, inspect it, pay them, etc.

I am now moving onto a barn conversion and doing this exactly the same way - planning was in place already but everything else is ad-hoc and via a LABC building notice.

Bundling into one company may be convenient, but the prices here illustrate why this is a very expensive way to do things. Each to their own of course :)
 
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We live in SOT and 3 years ago we put a 30m2 (3m x 10m) extension onto the back of the house and with careful planning and shopping around we did the structure including materials, windows, bifolds, electrics, plumbing, plastering and floor screed for £30k. Its a single storey with a tile pitched roof, 3m bifolds, 2 double windows. We had to put a 7m steel in as well. Architects wanted stupid money - £4k so we used an architectural technician, who charged £800 for the drawings and £550 for a structural engineer to do the calcs. I did all of the contracting myself

I appreciate prices may have gone up since but we were around the £1000/m2 mark for building. Fortunately we didnt need to reportage, we used savings and took on a small loan.
 
Associate
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Get a full technical drawing done by a professional before you start. This is the only way to accurately cost a build and shouldn’t result in any surprises.

DO NOT RUSH.

You’re lucky that you have a good builder on hand, but definitely get some other quotes.

Will do, Thanks you for the advice. Baby is due 1st July so we are planning to do the work after that sometime. Will get some quotes as well just so we have something to fall back on and when comes to comparing the prices.
My experience is the same as yours (although have required planning each time) Ive done lots of building work like this, i have always drawn all plans myself (planning has never had an issue with any of my drawings, it isnt hard, you submit them to the pre planning advice officer first anyway) - and then served a building notice to the LABC for building regs approval, you dont need any technical drawings at all for domestic, bar any local specifics such as calculations for complicated steels - these can be sandboxed to illustrate just that one element though if required - they'll inspect as you go and as often as you like.

Ive done 2* 2 storey extensions, a single storey extension, and a garage conversion (2 storey) this way. A total of around 150sqm in additions. Never cost anything even close to the prices quoted here. Break everything down, one contractor for groundworks, let them clear off, get it inspected, pay them, hire a bricklayer, get the walls done, get another inspection, pay them, hire a chippy, get the roof structure done, inspect, pay them, get a roofer in, inspect it, pay them, etc.

I am now moving onto a barn conversion and doing this exactly the same way - planning was in place already but everything else is ad-hoc and via a LABC building notice.

Bundling into one company may be convenient, but the prices here illustrate why this is a very expensive way to do things. Each to their own of course :)
Oh do I wish I had the know how and time to do it like you :D Having new born on the way and working 45 hour week I dont have that luxury. But you are 100% on everything you have said, that is the best way to go.
We live in SOT and 3 years ago we put a 30m2 (3m x 10m) extension onto the back of the house and with careful planning and shopping around we did the structure including materials, windows, bifolds, electrics, plumbing, plastering and floor screed for £30k. Its a single storey with a tile pitched roof, 3m bifolds, 2 double windows. We had to put a 7m steel in as well. Architects wanted stupid money - £4k so we used an architectural technician, who charged £800 for the drawings and £550 for a structural engineer to do the calcs. I did all of the contracting myself

I appreciate prices may have gone up since but we were around the £1000/m2 mark for building. Fortunately we didnt need to reportage, we used savings and took on a small loan.
I understand that architect would be needed for more complex jobs and that an architectural technician would be ideal for small extension such as ours. I know what architects do but would architectural technician have knowledge to advise us what best to do with space that we have (where to put bi-folding doors, windows, placement of your skylight, etc.)

Sorry if this all might be stupid questions, as a total noob when it comes to all of this every piece of information is greatly appreciated !
 
Soldato
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Im u
We built a single story rear 4x3 extension earlier this year. I drew plans myself, got a quote from a recommended builder, filled in the building control applications (permitted development), then he built it. It came to a little over £20k, including skylight, vaulted ceiling, windows, bifold doors, internal doors, plumbing, electrics, flooring etc... Oh, and retaining wall in the garden.

I just had to paint the walls and woodwork.

Im "up north" so not sure if it's regional, but some of the prices I see quoted on here seem crazy to me!

Im up north too and considering doing the same thing. which builder did you use?
 
Soldato
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Nottingham
My order would be:

  • Initial enquiry for remortgage, how much can I borrow, what is the house likely to be worth etc
  • Drawings - You will need to decide whether to go design and build and just have outline drawings produced for the contractor to design the detail, or get your architect to produce full construction drawings and be on board throughout the project. I'd much rather the latter as it lets me properly tender the works to multiple contractors on a like for like basis and gives me control over what I'm getting. The former is easier but you risk a builder saying "oh we didn't allow for that" or ending up with construction details you don't like
  • Cost of works - I'd avoid jumping into bed with one contractor too soon. Get at least 3 quotes
  • Remortgage
  • Instruct the works
In a normal market I'd be doing the same as a few others above and managing the trades myself as historically there's lots of savings to be had this week. In the curent market though I wouldn't be doing that approach. Trades are extremely high in demand and the small size of your project means those trades are likely to postpone/cancel for more profitable works. With a single contractor it's their problem to manage, if you manage yourself you could easily have abortive costs where trades further down the line can't start on time. There's a lot to be said at the moment for a contractor that has the key trades on their payroll.

As a compromise I'd be considering paying a principle contractor to manage all the shell works and getting the building water-tight then managing the fit out trades individually as the impact is less once you are water-tight.

Having said all that I'd planned on doing an extension to our house next year but there's no way I'm considering it in the current market. Record high prices of both labour and materials and a global shortage of materials means paying a huge premium of 50%+ with the risk that the extension could come to a standsill if something like the windows or roof gets delayed. I think there's a risk of people ending up adding over-priced extensions only to see house prices u-turn and being at risk of negative equity.

I'd seriously consider starting as a baseline of your property value 7 years ago and what it'd be worth with the extension back then. Will your mortgage still be well under this value once you've borrowed enough for the loan? Assuming house prices won't return to the prices they were 7 years ago may be risky, particularly around London where locality to workplaces is becoming less of a concern.
 
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Soldato
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Im u


Im up north too and considering doing the same thing. which builder did you use?

I'm just used a local builder - I'm in County Durham. Mail in trust if you would like details.

I used the builder for the majority, but got someone else in for the bifold doors and flooring. Obviously the price for works would depend on what you want and my quote was from ages ago, so prices may have changed since.
 
Soldato
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@Jez - I would love to project manage, but working full time made it impossible to do a decent job and things quickly fell to pieces when it transpired that our building firm were not up to the job and we had to push things ourselves. It would seem that people need constant supervision for even the most simple things.
 
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My order would be:

  • Initial enquiry for remortgage, how much can I borrow, what is the house likely to be worth etc
  • Drawings - You will need to decide whether to go design and build and just have outline drawings produced for the contractor to design the detail, or get your architect to produce full construction drawings and be on board throughout the project. I'd much rather the latter as it lets me properly tender the works to multiple contractors on a like for like basis and gives me control over what I'm getting. The former is easier but you risk a builder saying "oh we didn't allow for that" or ending up with construction details you don't like
  • Cost of works - I'd avoid jumping into bed with one contractor too soon. Get at least 3 quotes
  • Remortgage
  • Instruct the works
In a normal market I'd be doing the same as a few others above and managing the trades myself as historically there's lots of savings to be had this week. In the curent market though I wouldn't be doing that approach. Trades are extremely high in demand and the small size of your project means those trades are likely to postpone/cancel for more profitable works. With a single contractor it's their problem to manage, if you manage yourself you could easily have abortive costs where trades further down the line can't start on time. There's a lot to be said at the moment for a contractor that has the key trades on their payroll.

As a compromise I'd be considering paying a principle contractor to manage all the shell works and getting the building water-tight then managing the fit out trades individually as the impact is less once you are water-tight.

Having said all that I'd planned on doing an extension to our house next year but there's no way I'm considering it in the current market. Record high prices of both labour and materials and a global shortage of materials means paying a huge premium of 50%+ with the risk that the extension could come to a standsill if something like the windows or roof gets delayed. I think there's a risk of people ending up adding over-priced extensions only to see house prices u-turn and being at risk of negative equity.

I'd seriously consider starting as a baseline of your property value 7 years ago and what it'd be worth with the extension back then. Will your mortgage still be well under this value once you've borrowed enough for the loan? Assuming house prices won't return to the prices they were 7 years ago may be risky, particularly around London where locality to workplaces is becoming less of a concern.
We did consider moving but in current climate we will just stick it out here for another 5 or so years and then consider moving when our eldest gets to high school. That's the main reason we might as well get some extra living space that will make our life more comfortable.

We bought our house 7 years ago for £255k and now its worth £400k. We have £150k mortgage left so thinking of remortgaging back to £200k and that way we will have £50k to work with. It would cost us around £200 extra on top of what we pay now which we can afford easily. We have mortgage broker looking at all the sums.
 
Soldato
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cry.
This but I would do the first three at the same time as it is definitely worth having a dialogue with your mortgage lender to see what they would be willing to lend and on what terms as that could fundamentally alter your whole plan!
 
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Our extension finished a couple of weeks ago and overall we are really pleased.

To kick it all off we just invited a few builders around to get a general ball park figure of costs and timings. From there we moved onto the architect and then the structural engineer before choosing the builder.

Good luck!
 
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