rear extension - please talk to me about the process

[BoyMeetsWorld]

seriously, I'm clueless

I've researched the basic theory - budget, planning permission etc but no clue what the actual reality is - please can you share your experiences?

it's a simple single storey rear extension, 12 metres squared (3x4) to be used as a playroom (will need plastering, laminate floor, heating, lighting but no plumbing) and coming off the existing dining room.

main questions:
*what is the process for building regs & how much does it cost?

• do we have to knock down the adjoining wall or can it just be a separate room making use of the existing outside wall?
• how disruptive can we expect this to be (moving out isn't an option)
• what will happen to the patio we are building onto ?

Appoint an architect first of all, and get a builder to come and give you a ball park figure. Your architect may be able to recommend one. They will talk you through the building regs process and cost, and the builder will probably handle it for you.

I did this - it runs the length of the back of the house.

You need drawings. People who can do drawings sometime advertise in the local newspaper. Alternatively you can get an architecy to do it for you.

You need to have some idea of where you want doors / windows etc. I found it useful to plan what the room would be used for, so I could then decide where doors, windows, radiators, power points etc should be sited.

You may or may not need planning permission. You could check with the local council. You will need building regulations so the work will be checked by the councils building inspector and a certificate of compliance will be issued when the work is complete and has passed inspection.

I let the builders deal with the buildings reg section within the council. They are used to doing this.

I kept the original outside wall and keyed the new extension into it. I already had patio doors so they came out and created the entrance to the extension. I put a back door, patio doors, window into the extension.

I didn't find it disruptibe - but I was at work all day/ Yes, the garden is out of bounds for the children while it's being built. Most of the building is done before they knock through into the existing house. It's disruptive when they have to take power from the existing house into he extension and also when the central heating is extended into the new room. Other than that it was OK.

If you're thinking about a rear extension have a think about doing a front porch at the same time. It would be cheap to do it while you have the builders on-site and they just need to increase the amount of materials and time. Much cheaper than having them do it separately at a later date.

You, or the builders, have to lift the existing patio. You, or the builders, could relay it after the extension is complete, depending on what materials it's constructed from.

If it isn't complicated then you can get an architectural technician rather than an architect which is a lot cheaper. Draw out what you want, then contact a couple of architect people to get quotes for doing the drawings and advising if you need planning permission. You may not - depends on overall size, and existing extensions. The architecty person can give you ball park figures for costs.

The access is up to you - will be cheaper to use an existing doorway and keep the existing wall. It will need foundations so the patio will probably be dug up.

Windows are likely to cost more than walls (I think) - so work out how many windows and get ball park figures for those.

Once you have the plans approved, get written quotes (for the whole job not per hour or day) from three builders, and ask for references. Then choose which seems best - not always the cheapest.

Can save money by doing some yourself. If it is only a small extension then a small builder might be best, and you could maybe reduce cost by labouring, laying laminate floor etc.

Distruptive - depends on the build - if iit is a simple tag on with no knocking through then no big deal - just limited access to the garden probably.

thanks - that's really helpful :)

I wasn't planning on any knocking through, just taking off the existing French doors and using that arch way as the entrance. We do have a dog who needs garden access though - but there is 100 ft of grass behind the large patio so hopefully we could take her round & somehow get her over to the grass area do you think? otherwise how long do you thhibk the garden will be off limits for?

Please could someone explain what happens when they bring the electricity & heating through from main house & why this is disruptive?

thanks!

To join the electric you have to turn off the electric to the whole house - shouldn't take more than a couple of hours at most. Just need to make sure things like freezers are made as cold as possible before that.

Heating - probably similar - eg if you want a radiator it will need to be piped into the existing system which may need to be drained - if it is in summer should be no big issue. If standalone underfloor heating then likely no problem.

All things to talk about to the architect and builders before you start.

Access to garden - you would need to talk to whoever is doing the building - should be fine.

The key is to get definite plans on what needs doing and quotes for the job - broken down into quotes for individual bits - eg ground work, walls, roof, plastering, electrics, plumbing, flooring. Then you know exactly what you are paying for and if there is an unexpected overspend you know what to compare.

how much do you think realistically needs to be kept aside for unexpected overspends ?

At least 10%. But don't tell the builders that. Ensure the builders are doing it on an agreed fixed cost.
Keep it as your contiingency for unforseen costs that may arise.

We did an extension across the back of the house, and stayed in the house throughout the build. Ours was two storey so we definitely needed planning permission and building regs.

Given that your project sounds fairly simple, you might find builders that do design and build - they will get the plans etc drawn up and apply for planning. We had one quote for our job. The price was competitive but they weren't very creative.

You might need to allow extra budget for the electrics - we found that electricians are required to bring everything up to code, so we had to replace our perfectly functional fuse box for one that met the newest regs.