Quoted £200k for downstairs extension - Help!

[Limmers14]

As the title says, we’ve just been quoted £200k for a downstairs reconfiguration and extension which seems extortionate. We are based in St Albans which I know has a posh reputation and often means higher prices but wow, my husband and I are in shock! £200k doesn’t even include the new kitchen we need or things like cupboards in the utility.

I’d like opinions on whether this really is extortionate or if it’s the going rate. Screenshot attached of proposed new ground floor. The red dotted line shows where our current house and outbuilding are. We’d be making the living room a bit smaller, adding a toilet and utility, large kitchen extension.

The company is a well known local design and build company who have a good reputation for building well. They’ve been good to deal with so far.

What overall square footage are you adding?

We paid £135,000 for similar three years ago in the SE and that included the kitchen. This wasn’t cheap at the time. Even allowing for inflation yours sounds steep. Get some more quotes

I can’t tell from the drawings how much you are actually adding?

Copy and paste whole spec - external finishes, floor area etc into chatGPT - it’s actually very good on QS stuff.
certain things add a lot - UFH, bespoke glazing (that corner window might be), certain floor finishes etc.

Presumably you got more than one quote?

If they are D&B - is this their design? If you like them - sit down and ask how you can amend to get it down to say £150k. TBH £200k doesn’t seem a lot for a fairly large new space and other internal reconfiguration.

@KidsDoBetter @Polyestered We’re adding about 33sqm.

Our current house is within the red dotted lines, the red dotted lines includes a conservatory which we’d knock down. Essentially, our house right now is the size without the kitchen extension if that makes sense?

@Bridesmaid2026 Thanks for sharing. We’ll definitely be sending it to other builders.

@KidsDoBetter yes they are a D&B company. The price they’ve quoted is literally just the build, no UFH or floor finishes 🙈

Good idea about chat GPT. Would I need to use the paid for version?

So you’re doing a side and rear addition? I would think that removing and replacing the rear and side walls of the existing building will be adding ££££. You could do a box on the back of the house which would be cheaper.

Is it a single storey extension? To the back and side if I'm reading it correctly. We've just renovated a derelict property and prices rose weekly for some supplies! That does seem steep though.

I too would be getting more quotes.

@DeathBanana, not quite, we have a conservatory on the back of the house. So the kitchen extension is going in that footprint. None of our side walls are affected. So the design is a box on the back, albeit a box with a bit on the side to give us a larger kitchen.

@7238SM yes, a single storey extension

As well as getting in at least two more quotes, you also need to ask for a breakdown for all the quotes, including this one, so you can see where the money is going - how many people working on the job and for how long, materials for the different elements - glazing, electrical, plastering, carpentry etc.

So they don't actually need to remove any exterior walls and are using the original back door to enter the extension? That definitely seems expensive if this is the case, in essence they're just knocking down the conservatory and replacing it with a big single room.

Seems too high. I'm down south and I'm ah ing a double story side extension, new entire floor added (4 bedrooms, 2 bathrooms), downstairs rejigged all of it except kitchen is £207k

So is the purple line where you are now? And the blue all new?

@DeathBanana no, if you extend the blue line so that it links up, that blue line is the new extension. Remove the purple line (thank you!)

Purple line is existing conservatory that will be knocked down.

They may be quoting high because they don’t really want the job.

Yes kind of? The current entrance into our conservatory will be widened and I think the quote says new lintels and supports added.

Get more quotes. That’s outrageous.

Architects and builders can estimate typical prices using a "£x thousand per square metre" formula, but the total price will depend on specification and changes. A local architect would presumably charge you for advice.

A one-stop shop might add on something as you are paying for convenience.

I gather you are building on the site of a conservatory? Which will have no foundations, so this is ground-up.

I also live in St Albans, moved here from North London a few years ago. There is definitely such a thing as the St Albans Tax for sure - my neighbours just did an extension I dont know the costs but their builder was nice. DM and I'll send you his details if you want x

@Limmers14 - who drew up the plans and schedule of work you’ve put out to tender?

It’s important to issue the same to each contractor so you are comparing like for like. You need to be really clear what is included and what is not.

Coming out at the side and the rear add more cost than the same sqm on one projection because there’s more structural costs.
Obviously one quote isn’t that useful but I’ve known several people in London paying around that for a side & rear, plus you’re doing some internals.

I think Piglet John makes two important points. You are using a design and build company which is certainly convenient, however I suspect that costs more. And the point about putting a “proper building” on the site of a conservatory which is going to mean sorting out the foundations. Obviously you need more quotes though as that seems very high.

I'm sorry @Limmers14 but I can't imagine any parallel universe where I would fork out £200,000 for an extension on a house. The Royal family have bills like this for properties that have 30-40+ rooms, and are worth 10s of millions.

If you want somewhere bigger, then move. That is a batshit amount.

JMO of course before anyone comes at me. 😬

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The stamp duty alone to upsize in St Albans could be over £60k at a property price of £850k. Plus legal costs both ways and the covering additional property cost. Moving isn’t always cheaper.