Anyone built an extension recently? Any tips?

[NeatFreak]

We have decided we need an extension, comprising of a kitchen/ diner extension and up and over our garage to make an extra two bedrooms/ bathroom.

Having never even contemplated anything like this before, does anyone have any pertinent advice as to where we start?
We will probably have to remortgage but do we do that before getting quotes? Can we even get quotes without proper plans? We don't want to pay for plans if we can't afford to do it!

Dh mentioned something about drawing up rough plans and getting an architect designer (??) to draw them up rahter than asking an architect to do it all as it owuld save money- does that sound like a good idea?

Any pther tips or suggestions on practicalities or recommendations would be much appreciates [nervous and scared and wish we could press a button and have it done]

Look down your street and see if someone else has done something similar. Knock on their door and ask about builders or surveyors that they used. I always veer towards a surveyor rather than an architect if you are doing something relatively easy.

If you can't find a local similar example of what you want, look through the planning permission bit of the local council website at others people's plans. Great way to get ideas and they will normally include a surveyors name on them too...

Then visit a surveyor, get a set price for drawing up plans and a set percentage for project managing the build. This should include writing up a full spec, putting it out to tender, selecting builders and managing the day to day shit that will occur. Some people regard having a project manager as a waste of money, but I've always found that they save me money...in that the builders can't rip you off or wander off to other jobs as easily.

Good luck

Get proper plans that set out exactly what you want done and what the builder is expected to do. Given the scale of what you are proposing, you should use an architect as their cost will be quite small compared to the overall cost - I would guess that it would be about £50k but that is just a guess. - I think some architects give an hours advice for free.

We assumed that in getting a posh garage built, the price quoted would include the fitting of windows and doors, the builders thought otherwise. With only a verbal agreement, we didn't have a leg to stand on. That said they did a fabulous job and saved us several thousands of pounds.

I think if you ask builders for rough estimates, you won't get an estimate that is anywhere near the final price, we did this and final quotes for a 'turnkey' finished job were 50% more.

Builders will add a substantial mark up to the price of materials - maybe 30%. If you can get a recommended builder to work on a day rate, maybe with a fixed overall price for just doing the building work, source the materials yourself - get the builder to tell you in advance what they need when so it is on site when needed. You should also negotiate a trade discount with the builders merchant. I would only go down this route though if you have the time and are savvy enough to understand what they are doing.

Firstly consider if it's possible - i.e you will get planning permission. Your local council may offer advice at a pre planning clinic. Secondly work out the approx sqm for the extn and then you will be able to get a view of the costs from lots of sites but I agree with an earlier OP that says it could be at least £50k (but depends on where you are in the country). Although if it's a large extn with features such as bathrooms, bifold doors you are looking closer to £80k for a 2 storey exn. VAT is 20% and adds significantly to costs. If the kitchen has to be redone then that alone could be £15k once you add in flooring, windows, worktops.

Most builders and architects will give you a view of what's possible but don't rely too much on their estimates until you get firm plans. The plans are needed as they can only provide firm prices then. It will however be more than you expect especially if in the southeast.

We are doing a similar thing at the moment although only a single storey extension.

We had an architect round to see if what we wanted was feasible. The first visit was free and she has drawn up some rough sketches (still pretty impressive) to give us an initial idea.

With that she included her costs if we go ahead, all the council costs for planning and also her estimate of what it would cost us based on her knowledge of local builders. She also recommended builders she has worked with previously.

If we go ahead she will draw up detailed plans which can then be submitted for planning permission. We would then be able to use these and the building works schedule to get quotes from builders for the job.

Thanks, this is exactly what I was looking for. Some houses nearby have had similar work done but dh thinks we need something different, which would change the front aspect of the house (im not fussed on that part). 50k was the rough figure we had so we need to think about how to finance it- we have a small mortgage-free flat that we could sell or extend our mortgage on our own house so lots to consider.

We are also worried about having a negative impact on the neighbours so need to think about ways of limiting the interference.

Any ideas of timescales from initial quotes to completion? (impatient and broody!)

NeatFreak,

I would recommend employing someone to do the plans for you - some one who understands the development control system locally and building construction.

The architect/surveyor/technician title thing can be a bit confusing if you're not in the industry. Don't worry too much about it. If they claim to be a chartered anything you can check their professional membership/registration. Check out the previous work of whoever you choose. As beachyhead said above plug their name into the Local Authority site. Better still, get a recommendation.

You'll need two levels of drawings. One for planning permission which shows the Local Authority what you want to do; and one for construction, which is the detail for the builder to estimate off and the Local Authority to use for Building Control Approval (demonstrating that your building meets the Building Regulations).

If you employ someone to do your drawings they may have a list of contractors they work with regularly and can recommend for your particular job.

Get a break down of the estimate from the builder, so you can see where the money is going and an idea of when you'll need it. e.g. foundations are expensive and so are fitted kitchens, but they come at either end of the build. Agree a payment schedule, e.g. by regular valuation certificates from an Architect/Building Surveyor. Speak to your mortgage company - they may require valuation by a Chartered professional.

Allow a contingency above the estimate amount and you may be advised to keep a retention amount back for a number of months after the build is completed - the defects period.

You also need to allow for professional fees - architect/surveyor and structural engineer (for certifying structure for building control) and for Local Authority fees for planning and building control. Get their fee scales beforehand.

As mentioned above, don't forget VAT. It's a huge chunk of the total cost.

I think beachyhead was right, a lot of the headaches are eased by having a project manager to deal with it for you.

Go for it and Good Luck!

As a very rough guide you are looking at £1100 per sqm, if you tell me where abouts in the country you live I can give you the Homebuilding and Renovation guide to prices.

Draw out your extension on paper so you can see how big it will be, I agree about trawling the Council's website for planning applications as these can show you what other people have done.

Is your garage single skin brick? I had a double garage converted and only 1 of the garages had a bedroom over it so the side of the other garage was single skin, ie, one wall of bricks, no breeze blocks on the inside. This could mean that they need to reinforce the foundations of it.

The way I did it (garage conversion and plans for kitchen extension which will hopefully be done next year) was I knew a builder who had worked on several friend's houses and was mid-build on another friend. I bombarded him with questions before we had even bought the house, he recommended an architect.

I did the drawings to scale, architect copied them and builder quoted from that.

Couple of things from my experience.

As a starting point, might be worth using this scheme - www.architectinthehouse.org.uk/. You get an hour's free consultation with an architect for a donation to Shelter. We used this, got a local architect round who told us what he thought we'd be allowed to do (from his experience with the local planners). Also gave us an idea of the costs involved of having the drawings drawn up that we could then use to get quotes from local builders.

We're also looking to extend - 3 bed semi (in South Manchester) - kitchen already extends beyond the back of the house if you see what I mean by 3m. Plan is to extend dining room to same depth as kitchen, and then to put side extension on (part garage/ part utility / part kitchen extension). Think its about 11m x 2.5m. Single storey for part of the side, double storey for rear part (so not double storey all the way round if you see what I mean). Will hopefully get one bedroom and a small ensuite upstairs.

Have had one building firm round which has quoted £86k - thats for drawings, planning permission and build to "decorating state" - so all electrics / plumbing etc but does not include the cost of the new kitchen we'd need or the new bathroom and ensuite. Doesn't include the fitting of those either. It does include bi-fold doors though that I think are about £4k alone, and quite alot of lights / sockets. On that basis, depending on where you are, if you're expecting the £50k to cover the cost of the kitchen and the ensuite too, I think thats too low.

Have also had builder round (different firm) who has just finished a neighbours property (and comes recommended by the neighbour). He works slightly differently, and has indicated that his quote would be cheaper but not by much. Will probably use him though as he's come recommended.

Just one other point if you're re-mortgaging - the bank will only lend on the basis of the value of your property as it is now, not what it might be worth when the extension has been completed. That has caught us out.

Thanks again,so very useful. I think we have enough scope to extend the mortgage based on its current value but we would have to rebudget our monthly outgoings...
We are in the south west, bristol area.
A few neighbours have had work done recently so I may send dh round to talk to them.
We are setting time aside this weekend to go through everything so all the info on this thread will be very useful

Hi Neatfreak

We spent all of 2011 renovating and extending a house. I blogged the whole thing from moving in to the finished job - my intention in blogging was to provide others with a 'real time' idea of what was involved with the process, so it includes the ups and downs and some idea of the costs of unforeseen jobs.

You can view the blog at sixtiespalace.blogspot.com and scroll backwards through the months at the bottom right hand side to Jan/Feb 2011. It might give you an idea of the order we did things in.

we are having an extension at the moment - we have found we needed to demolish the garage as foundations not ok for an extension on top of garage. So having new double garage, new utility, extended kitchen, remodelled bathroom and downstairs toilet plus two new bedrooms both with ensuites.....!£100K