Process of Quoting for a House Extension?

[adzyp]

Hi everyone,

We are currently in a 3 bed detached with a good amount of space at the side of the house which we are thinking about extending into with a double storey extension.

Only thing is I don't know where to start?

Do I get a few builders round to discuss our options or do I need to get an architect in first before a builder will even entertain the idea?

The main thing is knowing roughly how much its going to cost before we proceed but don't want to be spending a big chunk on architect fees etc. just to get to an idea of price

 

[^woody^]

You need a designer first. They will advise on what's possible and how much it will cost.

Builders build to the designers plans.

 

[noseall]

I don't mid doing a pre-design visit and looking at the feasibility of a build. I'm one of the good guys though. A lot of builders are too busy to care, especially if the job is likely to go to another builder.

The best most builders will offer is a figure of £1000 p/sqm per floor for the building work.

 

[Notch7]

You could take a pic of the location and then up load onto the forum along with a sketch of what you want with a few dims.

Im sure there must be builders who can give you a rough ballpark, or a price range. That would tell you if your budget is at least on the same page or not.

Square metre rates are a bit of a guide, so you could ask around what they tend to be currently.

If you are still standing then talk to some local builders. There is a frequent contributor on this forum that is a builder in Staffordshire, so he may be able to help.

 

[^woody^]

Planning constraints, can it be built? Will the builder know?

He may or may not know about public drains, ground conditions and access, either of which could make a significant difference to the cost.

Try £50k if everything is straight forward and add 50% for London a bit less for the home counties. All fees about 8%.

 

[adzyp]

I don't mid doing a pre-design visit and looking at the feasibility of a build. I'm one of the good guys though. A lot of builders are too busy to care, especially if the job is likely to go to another builder.

The best most builders will offer is a figure of £1000 p/sqm per floor for the building work.

Just tried to message you but wouldn't let me...

What sort of thing would you be able to advise on without a design?

Is it really the same price per sq/m for the second floor, would have thought the second floor would be cheaper.

Lets just say its £1,000 sq/m whats includes in that, would that be the digging up and laying foundations, knocking through walls, moving any gas/electric, internally finished etc. or would that literally just be the building blocks with everything else needed on top?

 

[adzyp]

Planning constraints, can it be built? Will the builder know?

He may or may not know about public drains, ground conditions and access, either of which could make a significant difference to the cost.

Try £50k if everything is straight forward and add 50% for London a bit less for the home counties. All fees about 8%.

The property has had planning approval in the past before we moved in so hopefully no issues there.

So what are you saying:

1. Get a designer to design it all and estimated cost
2. Get planning approval
3. And only then start trying to find a builder to do it? Which potentially may increase the price again

 

[noseall]

What sort of thing would you be able to advise on without a design?

A decent builder would look at the building footprint and see if it clashes with any drains etc.
He would look at proximity to trees, shrubs and advise how this may affect.
He would look at how the roofs would tie in together,
He would look at existing drain depth and whether any new drainage proposals are feasible.
Access to site.
Logistics.

Is it really the same price per sq/m for the second floor, would have thought the second floor would be cheaper.

The second storey can be cheaper if the roof is simple. It can also be more expensive if the roof is hipped and furnished with plain clay tiles, for example.

Lets just say its £1,000 sq/m whats includes in that,

All the building work up to finished plastering, skirts and architraves fitted, doors hung, windows fitted etc.
​

 

[adzyp]

Thanks all, certainly food for thought. Just measured up, approx 8m x 3m so 24 sq.m. So i suppose the £50k isnt far off.

Wasnt expecting it to be that much or certainly wasnt hoping it to be!

Guess we need to weigh up the option of doing it and staying put (and what we would actually gain) or just using the money to move house

 

[^woody^]

The property has had planning approval in the past before we moved in so hopefully no issues there.

So what are you saying:

1. Get a designer to design it all and estimated cost
2. Get planning approval
3. And only then start trying to find a builder to do it? Which potentially may increase the price again

Unless it's going to be exactly the same, then you can't use a previous permission as an assurance that a new application will be approved.

The designer designs what you want (if you can have it), and the builder builds what the designer specifies. After planning approval comes the building regulations. The builder needs to know how it's all gone to be put together, only then can he give you a quote once the build regulation design is done.

Finding a builder to do it, won't increase costs. I don't know how you work that out. The builder is the only one who knows the costs because he is quoting them.

 

[adzyp]

Unless it's going to be exactly the same, then you can't use a previous permission as an assurance that a new application will be approved.

The designer designs what you want (if you can have it), and the builder builds what the designer specifies. After planning approval comes the building regulations. The builder needs to know how it's all gone to be put together, only then can he give you a quote once the build regulation design is done.

Finding a builder to do it, won't increase costs. I don't know how you work that out. The builder is the only one who knows the costs because he is quoting them.

Sorry just misread your first post saying the designer will advise whats possible and how much it would cost

 

[tomfe]

Wasnt expecting it to be that much

Just out of interest how much did you expect to pay for a 50sqm 2 story extension?

 

[adzyp]

Just out of interest how much did you expect to pay for a 50sqm 2 story extension?

Well it was more hoping not that much than having any expectation.

Also that was the first time id measured.

Its only been the past week we have looked at maybe moving and then today considering maybe extending

 

[tomfe]

Well it was more hoping not that much than having any expectation.

Also that was the first time id measured.

Its only been the past week we have looked at maybe moving and then today considering maybe extending

I was not being funny, I was just wondering what figure you had in your head when you first started to discus an extension.

 

[adzyp]

I was not being funny, I was just wondering what figure you had in your head when you first started to discus an extension.

Its ok i seriously had no idea. I said it could be anything between 20k and 60k for all i know. Obviously the cheaper the more likely it would be to have done but now im thinking its probably cleaner and less stressful to move to a 4 bed instead at some point, cost wise probably wouldnt be much different