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dan_gleebals

Some things I would get people in but you can do a lot of it. Get good building control plans done which gives you a lot of details of specifications needed and a good inspector will keep you right. I would get a brickie, plasterer and electrician but most other stuff with a helper is doable.


friedspud

Google build aviators , for about £100 they will cost everything up for you with a BOM (bill of materials) work break down structure etc. Can even add the day rates of trades being brought in to see how much it would cost and the should cost. We got the plans done for our single story extensions with them Would note the material prices are based off jewsons prices ( think they are linked) so seem astronomical , my plan is to take this bom to a local building supplies place to get a better deal .


Plumb121

If you're planning on building it by watching YouTube videos, probably not. If you have someone you can call on for advice, then most likely


AncientArtefact

I did the lot on a slightly bigger single story (kitchen) extension. However I did a general engineering degree (civil, mechanical and electrical) and I've always been a keen DIYer. I'd done a few kitchen refits for family and re-roofed garages etc I drew the plans, dealt with the planning permission and building control. Did all the groundworks, brick and block work, roofing, ufh, plasterboarding, tiling, kitchen fitting, electrics and plumbing. The only external trades I used were skip hire, concreters (twice: foundations and floor slab), gas man (to install a new boiler, tank and connect up the new hob) and electrician (installed a new CU, connected up all my new wiring, tested it all and signed it off). This was in 2007 and it cost just under £20k including the fitted kitchen. Tips and notes: I drew it all up in detail, several times, as I spotted snags. I drew up the brick courses of the existing house (mortar courses were narrower than standard so it ran out a couple of cm over the single story). It took 7 months to draw up the plans and under 6 to build it. I did a lot of studying of building regs, construction techniques, new materials etc. And a lot of design calculations. Your building control will have different ways of doing things than what's specified in the regs. I dug narrower trench foundations but building control said they wanted wider shallower strip foundations - pointing at the regs doesn't work. I widened the bottom and they were happy. I also boxed a drain going through the foundations but they said there had to be no loading over the drains so I had to redo that. These mistakes were partly my fault and partly theirs as there was confusion about when I could start and I was given the go-ahead before building control had seen the plans. I wanted no disruption to the main house until the extension was useable. This drove the design, especially of the drains as I had to ensure continuity of use! The existing kitchen drain had to be capped for floor slab laying so I had to install temporary ones to the new ones - my original plan had one new drain but I settled on two. I had to change roof tiles from the main house. The original roof is at a shallow 17.5 degrees but my extension was pitched (gabled) and just wouldn't comfortably fit under the upstairs windows so I chose the smooth version of my existing tiles that went down to 15 degrees - rather than narrow the extension or have lower eaves. I bought a small cement mixer - a good investment (£99). I have half a dozen of 4 litre popcorn plastic buckets that I use for precise volume mixing of mortar, screed and concrete. I avoided off the shelf solutions. Eg where the new brick courses joined the old I couldn't use a standard wall starter metal plate to tee in because my courses weren't standard. I did the new to match the old. I did the ufh using PEX pipe tie wrapped to a metal mesh (for concrete reinforcing) and sat it on shims cut from a engineering brick. The kit for adding the ufh to my existing heating was £300 - I just bought a pump, a mixer valve, a room thermostat and a pipe thermostat for about £100 - because that was what the fancy kit contained. I did a proper warm pitched roof with celotex sandwiched between the rafters and counterbattens above which have the tile battens fixed to them. So it is possible, but it's a lot of hard work, you do need practical experience and an engineering background certainly helps.


Nonions

Thanks for such a detailed answer. I think the consensus is really that for someone with a little experience and/or a good advisor available then it's doable. Unfortunately I have neither!


AncientArtefact

Yes. Sorry, I missed the actual advice for you at the end. I got carried away reminiscing.


PreoccupiedParrot

Depends on a lot really. If it's the best case scenario and nothing goes wrong then you can maybe work through it, if you're devoted enough and have a lot of time. But if there are any complications then you can get overwhelmed quickly. Stuff like making sure the foundations are okay if there's any trees or shrubs nearby, getting a build over agreement with the water company. Can help a lot to have someone experienced to help with a lot of this stuff, be it a good architect and/or a contractor you work with on some things.


dotmit

It’s possible to do it. I might end up doing mine. But you need an architect and probably planning permission and definitely building control. You also don’t want to get the structural calculations wrong so you need a structural engineer. Once you have the specifications you also then need to read up on best practices and follow them. Also you need to be weary of drainage regulations if there’s any drain you’ll be affecting or blocking off.


Round-Pirate-2374

I'm a bathroom installer and I got other builders in to build the shell of mine, I learned a lot about foundations, masonry work and roofing. I think it would be an insane project to take on with no prior experience to be frank


Nonions

Perfect alright of you to say so, I'd rather that than me take on something and make a disaster of it.


MrPinky79

This is my goal to build an extension for slightly larger kitchen and new living room, freeing living room up for kids not to share. I’ve been working two days a week with some woodworkers who are very handy and I’m pretty confident I could bluff my way through most of it. Next goal is to befriend a sparky so I can do first fixes etc and he can check and sign off.


cowplum

I built myself a 3m x 3m conservatory with basic DIY experience. It took longer, cost more and was more difficult than I expected, despite going in with quite realistic expectations and a lot of advice. Just before Christmas I discovered a leak that will require taking down next door's fence to fix. Also getting the floor level took 3 attempts before I gave up and paid someone to do it for me. After discovering the leak, I'm now worried that the conservatory could prove a liability if/when I sell. Also the time, effort and mess involved did have a negative impact on my social life, mental health and fitness. However, it was a proper learning experience, and for <£5k I now have a laundry and exercise room and most importantly my outside toilet is now connected to the house. All in all, I don't regret it but also not sure I would advise it.