Self-build Small Extension

We have a single skin coal house on the rear of our property, now used to store the washer and dryer. It is currently accessed from the rear door to the house. It works but it is a small room and when we have children it would be much-needed additional space. The room is already powered by a dedicated circuit on the CU and the plumbing has been done well with copper piping (no push fit).

I want to demolish this small room and create a small utility room. I have (poorly) annotated a picture below for reference, but to summarise the plan is to remove the window on the left and replace with patio doors and steps. The extension would then stretch from the right and up to the patio doors. The current rear door would become an internal door and the floor height of the extension would be the same as inside the house. You will notice the house is fairly high up as it was built before our floor defenses were.



I have checked the planning portal and it seems I would not need permission or neighbour consultation. This is because it would be within the dimensions of a small permitted development. It must be noted that most houses on our road have large extensions. I will have a groundwork friend who can dig trenches and luckily I have secured a large number of bricks from a similar property down the road. Because of the access to these bricks I'd like to build a solid wall to match the current construction.

So my question at this point is to ask for recommendations on learning resources -- are there any good websites or examples of projects? I will get onto some bricklaying courses but before then it would be good to get some reading in first. Thank you.

What’s your background/existing skill level? How much are you hoping to DIY?
In any case, a good first step is to get some building regs drawings done, and get them submitted and approved, you then know the main construction methods to start thinking about.

23vc said:

What’s your background/existing skill level? How much are you hoping to DIY?
In any case, a good first step is to get some building regs drawings done, and get them submitted and approved, you then know the main construction methods to start thinking about.

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My profession is unconnected to the proposed work but I have gained good experience on jobs at this house including installing a lintel, building a large gazebo/deck, laying a large patio on 250mm of hardcore and sand/cement, opening two fireplaces up, tiling and dry lining/insulating walls. I will have help from a friend who has years of work in groundworks, plus various people who have very specific but skilled experience in their own areas (installing windows and roofing being the main two). As I say I will get onto some courses too for experience.

In terms of what I'd like to DIY, the aim is everything excluding the window to door conversion which I will give to a builder given it involves a span of opening I'd be uncomfortable working with. Below is a list of everything I can currently think of (in no particular order) which I would be DIYing. This obviously excludes issues found on site along the way and I have not gone into detail on every aspect -- it is just an outline.

- Demolition of the existing build and safe isolation of plumbing and electrical supply
- Creation of trenches and pouring of cement
- Foundation and wall construction, installation of UPVc window
- Construction of tiled 'lean to' style roof with guttering
- Conversion of external door to internal door
- Installation of joists and flooring
- Plumbing and electrical circuit
- Insulation and plasterboard
- Fit out (furniture, flooring, decoration, etc.)

Be interesting to know if there is anything major I have missed out on. Please bear in mind I don't plan to start until 2021 which gives time to save and learn.

a few points:

check drainage -you need a build over agreement if building within 3 metres of a public drain. You need to make sure there arent manholes in adjacent gardens with a foul run going across your garden. I was involved in a job that had a 3.2m deep foul with that situation. Its pretty unlikely but be aware and rule it out (same with water, gas, electric).

Your foundation may dig across a soakaway pipe run if the soakaway is in the rear garden. If the soakaway is close to the new extension you might need a new one.

do your research on soil type and any trees in the zone of influence so you dont have a surprise on trench depth.

The extension will make the room to the left darker....maybe the new doors will mitigate that.

Notch7 said:

a few points:...

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Thanks a lot for raising those concerns -- these are exactly the sorts of things I want to think about now so I can plan this properly over time.

Luckily on those points I think I'm covered. There is a foul drain that runs between all properties. I noticed this on the deeds and have physically located it buried fairly shallow at around 4 metres away from the rear of the property. There is one manhole cover for every two houses and luckily it is next door who have the cover on their land for both our houses. They told me it directly resulted in them having to have a narrower extension when they build theirs'.

The only soakaway is at the front of the house for runoff from the driveway. Waste water goes into the soil stack and water from the guttering runs into a drain.

Luckily no trees and the ground is a mix of soil and clay until about 0.6 metres down when we start to hit sand (Lafarge Tarmac have a pit nearby).

Just been looking at the processes for going through building control too, wow it's expensive! Seems like there's a lot to take into account too. I need to sit down and gather as much as I can on the process start to finish and produce a checklist. What would people say is the best approach -- full plans submission or just building notice? Had experience of neither.

In the meantime I just need to think about every aspect of the build and how I'd tackle it. With regards to drawings what level of detail are they looking for? I genuinely don't know. I use Autocad at work and there are people in my department who have used it for 25+ years.

cwhaley said:

Just been looking at the processes for going through building control too, wow it's expensive! Seems like there's a lot to take into account too. I need to sit down and gather as much as I can on the process start to finish and produce a checklist. What would people say is the best approach -- full plans submission or just building notice? Had experience of neither.

In the meantime I just need to think about every aspect of the build and how I'd tackle it. With regards to drawings what level of detail are they looking for? I genuinely don't know. I use Autocad at work and there are people in my department who have used it for 25+ years.

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for a DIYer full plans every time.
under a notice the building inspector will tell what you've done wrong after its been done.

you could choose a private inspector as an alternative -costs are about the same, but they can be more pragmatic about interpreting the regulations.

one thing to note: building regs drawings prove a building is constructed to comply with the building regulations, it isnt a working drawing, so it wont be dimensioned.

Notch7 said:

for a DIYer full plans every time.
under a notice the building inspector will tell what you've done wrong after its been done.

you could choose a private inspector as an alternative -costs are about the same, but they can be more pragmatic about interpreting the regulations.

one thing to note: building regs drawings prove a building is constructed to comply with the building regulations, it isnt a working drawing, so it wont be dimensioned.

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Thanks a lot Notch. For someone in my position it's very easy to get overwhelmed with the vast amount of information out there. It helps to understand what I should have ready to submit.

So with the full plans approach it sounds like an inspector will visit the site at key stages of the project to inspect, which from my point of view is something I'd prefer. I have no idea what the local inspectors are like but if they get to see the works at every stage they are interested in I'd rather be told what I'm doing right/wrong at that point rather than go back and repair at the end.

I'm capable of producing drawings showing the face of each wall (where the windows, doors, etc. will be), the roof and pitch but nothing technical. Sounds like producing a drawing/plan is something I could do for this.

cwhaley said:

Thanks a lot Notch. For someone in my position it's very easy to get overwhelmed with the vast amount of information out there. It helps to understand what I should have ready to submit.

So with the full plans approach it sounds like an inspector will visit the site at key stages of the project to inspect, which from my point of view is something I'd prefer. I have no idea what the local inspectors are like but if they get to see the works at every stage they are interested in I'd rather be told what I'm doing right/wrong at that point rather than go back and repair at the end.

I'm capable of producing drawings showing the face of each wall (where the windows, doors, etc. will be), the roof and pitch but nothing technical. Sounds like producing a drawing/plan is something I could do for this.

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Full plans submission means supplying drawing annotated to explain how the construction will satisfy each part of the building regulations.

The plans get checked and if approved, provided you build as per, you should get the final cert.

Under a building notice nothing is checked in advance. The inspector will only be able to tell you what youve done wrong.....after you have built.
Im not sure who would build that way. Many builders wont even price a job without building regs drawings. A building notice is risky for a builder, it creates big grey area, contractually there are no specifications.

Notch7 said:

Under a building notice nothing is checked in advance. The inspector will only be able to tell you what youve done wrong.....after you have built.
Im not sure who would build that way. Many builders wont even price a job without building regs drawings. A building notice is risky for a builder, it creates big grey area, contractually there are no specifications.

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*waves*

Though I won't comment on whether it's the smartest or not - I did it because the challenge was not to pay anybody else to do anything, though looking back I probably could have produced compliant drawings! I've been using https://buildingregs4plans.co.uk to have something to work to, and I've checked my next steps with the BCO at each stage

23vc said:

In any case, a good first step is to get some building regs drawings done, and get them submitted and approved,

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- yes

Notch7 said:

for a DIYer full plans every time.

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-yes

VDubDan said:

I've checked my next steps with the BCO at each stage

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- but that isn't really how Building Control is supposed to work

I’ve used private and council for building control in the past and found both to be fine, but on the current one the private firm keeps sending me strongly worded letters stating that I’ve “still not” had a final inspection, and that until I do so my home insurance is invalid, and they may need to revoke the original building notice they put in on my behalf, and the council may need to expose all the work, etc. Which although is a standard letter, it pees me off a bit as I’m stressed out enough trying to get it finished, and it’s all been passed at every inspection as you’d expect.
As opposed to the council, who always seem to just state that you can take as long as you like as there’s no time limit.
Might just be me though, others may have different experiences. But actual inspection/advice wise, not much difference, as above private can be a bit more flexible at times.

23vc said:

I’ve used private and council for building control in the past and found both to be fine, but on the current one the private firm keeps sending me strongly worded letters stating that I’ve “still not” had a final inspection, and that until I do so my home insurance is invalid, and they may need to revoke the original building notice they put in on my behalf, and the council may need to expose all the work, etc. Which although is a standard letter, it pees me off a bit as I’m stressed out enough trying to get it finished, and it’s all been passed at every inspection as you’d expect.
As opposed to the council, who always seem to just state that you can take as long as you like as there’s no time limit.
Might just be me though, others may have different experiences. But actual inspection/advice wise, not much difference, as above private can be a bit more flexible at times.

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My experience is that private inspectors, if big companies are profit driven. I know some inspectors have 300 jobs on their books at any time.

Notch7 said:

My experience is that private inspectors, if big companies are profit driven. I know some inspectors have 300 jobs on their books at any time.

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Maybe that’s part of their motivation for trying to get each case closed off within a timeframe then. As I understand it, there is no time limit whether using private or local authority. I’ve no idea if and why they’d “revoke” the application, sounds like a bit of a threat. I’ve been doing mine 2.5 years, so yeah it’s a long time, but I’m sure there are many that are longer, for whatever reason. Anyway sorry to hijack the thread slightly, just thought I’d mention it