Extension timeframe, what's realistic?

[fastliving]

I'm planning on extending this year, will need planning permission.
Just looking at architects now, and was hoping to get the work done this summer (prob about £70-£80k of work to give a sense of scale - double story wraparound).

Have been took that building this summer is unrealistic, what are everyone's experiences with how long it takes (providing planning and finances goes smoothly?)
Thanks

We're having an extension too. It took 12 weeks to get planning consent (from first appointing architect to go-ahead from council).

We're now getting builders quotes as we didn't want to do so before we were sure what the project would involve.
Once we've got builders quotes, we're expecting to have to wait until the builder can fit us in. Possibly 2-6 months. We've been told to avoid builders who say they can start immediately as it implies they're not sought after by lots of customers.

Then the build will probably take 10-12 weeks or so. Single story plus a few bits of interior rejigging.

So you could be done in 12 months total @Gazelda ? Even as a conservative estimate.

I think that's realistic for us. But I guess it depends on your own council, complexity of the project, builders availability and weather issues.

We started looking for an architect, waited for the plans, then applied for planning permission, then waited for our builder, then the build - was two years from beginning to end. The longest part was waiting for the builder but every good builder round here is busy - it was worth the wait too!

Took 18 Ma this start to finish. We needed planning. Build itself took 4. 1/2 months.

Neighbour did one smaller. Took 10 months start to finish but was unlucky as council messed up as required planning and not permitted development. But got the time back as builder had availability on completion of tender so started straight away.

Sensible time is one year but availability of builders can be a massive issue currently. Round us there is normally a 6-8 month wait

We knew that the builders we wanted - they'd done a friend's extension - are always very busy. So we asked them to come first and give us a very rough quote. We accepted that and as it was a ten month wait before they could start we had plenty of time to sort architectural plans, permission, water board permission, etc. It was worth the wait and they were superb builders, they did an excellent job and the whole process was very easy. (Apart from the dust. There is a lot of dust when a wall is knocked through )

What took the most time for us was waiting for the builder. He is very good and reliable, and consequently very popular!
Plans drawn in December 2014, planning permission and building regs achieved by the end of March 2015. Build started mid August 2015 and finished end of January 2016 (very large extension).
Good builders are always going to be very busy.

It really might be worth trying to line up builders as planning goes in? To try and minimise the wait?

I'd certainly ask around friends and family locally to find out if they could recommend a builder. And if you know what you want from the build then you could ask them to have a look. We had a very clear idea of exactly what we wanted and the initial rough quote was very close to what we actually paid. I'm sure you will have done this already, but do factor in a contingency fund. We were thankful we had because the survey of the drains found that they had tree roots growing into them and it would be sensible to replace them rather than build over them and face a problem in a few years. I sleep happy knowing that my toilet flushes safely.

And a decent builder should have a good idea of whether the planning is likely to go through or not and how long it will take.

@fastliving worth having a look at builders but the reality is no good builder will give you a firm price mm TIL they have seen the plans and importantly the building control spec added to the plans. We then did a tender exercise with I think 5 builders starting. Quickly narrowed to three and did a full tender exercise with that and a draft contract that we drew up. The builder we wanted wasn't the cheapest but was disappointed not to be given it so dropped his price. Ours was attractive as we were flexible on start dates which meant with ours lined up he could finish his existing job and move straight in to ours. Had a full order book for 12 months then and that helped on price

A extension takes between 8-12 weeks then there is the plans drawn up planning permission etc .
We started ours January architect drew up plans then submitted planning permission approved about April. I think then by time we got agreed builder start date was end of July, was delayed then till August then work moved fairly quickly but due to more delays due to our builders sub contracts it was 95% ready by Christmas. Then we had to chase the last bit of work January. My experience get a reputable builder with lots of references , the best you can afford so you don't get let down and prepare for lots of headaches.

OP, we used design and build, so our builder was 'on board' from the very beginning, even so, he is constantly booked up to a year/18 months ahead. Be very careful about chosing your builder. Ask for personal recommendations. There have been some truly horrible stories on here about people being ripped off.