Part Fifteen – The Site Is Finally Ready

This fifteenth entry was published originally by JSHarris on the 18th September 2013 and received 2,030 views on the closed forum

After all the ups and downs of the past few weeks, the frustrations over dealing with the utility companies and the stress of having so many problems with the borehole, we are finally ready to start the real build. We’ve also had some good news from the valuer, it seems our completed house is going to be worth around £20k to £30k more than we thought, and even the plot is now worth £40k more than we paid for it a year ago, and that was before we put in the services or borehole.

I’m afraid there are no new photos, as all that’s changed on site is the removal of all the heavy plant. The expensive borehole for our water supply is now just a bit of 4″ blue plastic pipe, sticking out of what will be the garden (although it does go down almost half the height of Salisbury cathedral spire!). It is very spooky looking down it, especially as when I did my mobile phone nearly slid out of my shirt pocket and down the hole. It hasn’t got a massive yield, but will be ample for our modest needs and should save us around £600 or so a year in water charges. I spent half an hour a few days ago working out the likely running costs, as we now know pretty much which Council Tax band the house will be in. It looks as if the FIT income from the solar panels will just about cover the Council Tax, water and sewage will be, to all intents and purposes, free of charge and we’ll be generating more electricity through the year than we’ll be using, so we shouldn’t really pay much in the way of electricity bills, either. I think the annual running cost of the house (electricity, Council Tax, water, sewage, internet and telephone) will be somewhere between £400 and £600 a year. Given that our only form of heating is electricity this seems to be quite reasonable to me, and a great deal less than we pay to run our current house.

One question I’ve not really answered so far is how we’re dealing with some of the bureaucracy involved in a self-build project. We have no project manager (other than me), no architect (not even a technician) and my knowledge of the building trade, planning etc is only that which I’ve gained from some very small scale DIY jobs over the years, the answers to questions asked on the forum and some reading up on various regulations. I think I covered getting planning permission pretty thoroughly in the second part of this blog but so far I’ve not mentioned much about Building Regulations Approval. If I’m honest, building regs was the one part of the process that really unnerved me at the start. There’s a dearth of readily available information on what needs to go into a Building Regs application, in terms of the level of technical detail, and we were trying to seek approval for a house and foundation construction method that was radically different from a conventionally constructed “estate house”.

I’ve no idea how others go about this process, but here’s what I did. I filled in the Building Regs Approval form from our local authority, and sent it off together with a set of plans I drew up (the first five files below), with a bit more detail than those I submitted for planning (but with little in the way of constructional detail, as I wasn’t sure quite what the detail was going to be). I also submitted a letter with some additional information (copy below) together with the foundation system structural report (also copied below).

Site Plan – Services – A2

Floor Plans – A2

Floor Plan – Services – A4

Access Plan – A4

Elevations – A2

Additional information

Self-Build, Fovant-Self-Build-Predicted_EPC

Kore Insulated Foundations Report

I had four queries back from the BCO, the first asking if I could confirm that I would be fitting linked smoke/fire alarms, the second asking for details of the ventilation arrangements, the third requesting details of the guarding to the stairs and the last asking if I was going to use a Part P qualified electrician or use the LABC to sign off the electrics. These were answered with a short letter (below).

Additional information – Addendum

Within a couple of days I received a letter granting conditional Building Regulations Approval, subject to some further detail being provided on the frame structure and the normal inspections. We got on with the ground works and had the first inspection from the BCO when putting in the drains. This went OK and the next scheduled inspection isn’t until we are ready to pour concrete into the insulation that forms the mould for the slab. There was no requirement to inspect the foundation excavation or stone fill, presumably because this foundation system can be used on soils with a pretty low bearing strength and the soil where we are is known to be pretty hard.

To close off the remaining structural details (but not really knowing quite what was needed) I asked MBC Timberframe for some frame drawings (which were based on the CAD files I’d sent them). I then re-drew these to tidy them up a bit and added a lot of notes giving details of the specification and build up of the walls, roof floors etc, and sent these off to the BCO (see below). Some of the structural detail had changed slightly (I’d not realised that the original wall and roof insulation details had been superseded by MBC, for example).

Elevation – Section showing foul drain stack – A4

Floor Plan – Revision 5 – A4

Elevation – Sections for BC – A4

Elevation – Sections – Revision 2 – A4

An hour or two later the BCO got back to me saying these were fine and had all he needed, and that we can carry on till the next scheduled inspection.

So far I have to say the process of gaining Building Regs Approval hasn’t been too painful at all. It has involved tracking down a lot of detail and has meant me having to learn the regulations almost by heart (mainly so I could get the initial design right) but the process itself hasn’t been that daunting. I feel that now the worst of the bureaucracy may be over, as anything that comes up from now on in the build are likely to be practical problems, and those I feel far more confident at tackling.

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ProDave 18 Sep 2013 05:37 PM :

 Excellent news. Have you had the borehole water tested yet? and is the drainage system installed yet?

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Alphonsox 18 Sep 2013 07:15 PM :

 Thanks for sharing this level of detail – It makes me feel a little less apprehensive about the process.
What CAD package did you use to generate the drawings ?

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jsharris 18 Sep 2013 07:16 PM :

 Yes, the borehole looks to be OK for more than we’ll need, the consensus is that the yield may increase slightly, if anything, as the very fine gault muck from the higher part of the hole may be blocking the water a bit, where it’s been blown in to the more permeable rock by the mud pump pressure (and the static head of water in the 70m deep hole, which is over 6 bar on its own).

The drainage is in, too, a BioPure package treatment plant that drains to the stream just over the lane.

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jsharris 18 Sep 2013 07:25 PM :

 Thanks guys, I thought it might help others through this process, as when I started looking for what was needed for BR approval I couldn’t find much to help anywhere.

I started off using AutoCad for the drawings (only because I had a copy already) but soon switched to the much simpler Autosketch product from the same company. Unfortunately Autosketch isn’t now available, but it really is about as simple a 2D CAD package as you can get, and perfectly adequate for doing planning and building regs drawings.

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ProDave 18 Sep 2013 09:08 PM :

How did you get the effluent across the road to the stream? I take it that’s a pipe under the road?

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 jsharris 18 Sep 2013 09:29 PM :

 Yes, just a bit of 50mm MDPE pipe going across 3m of lane. I needed a highways licence to dig across the road, plus ground works guys with a highways permit, but it was only a couple of hours work to put the trench in, lay the pipe across to the stream and make good. The council did send a chap out when the work was being finished to make sure the reinstatement was up to standard (had to do something to justify the £355 fee for the highway licence………..).

The pipe is small bore as it only carries fairly clean treated water, plus it’s pumped, primarily to allow a small bore pipe and avoid rats being able to get in to the treatment plant from the stream. We could have used 110mm pipe and a one-way anti-rodent valve, but space was tight, and the one-way valve would have needed an access point that would have been in an awkward place.

I don’t mind the pumped solution, as it also allowed us to run the pipe through a couple of right angle bends and not have to worry about keeping a fall. The pump can deliver over 200 litres per minute, so will at most run for around 2 minutes per day (it sits in the treated water chamber in the treatment plant and operates on a float switch).

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 ProDave  18 Sep 2013 09:34 PM :

 Same system as we will use, except ours will discharge to an above ground made up soakaway mound. We have been instructed that direct discharge is only an option if there is no room at all for a soakaway system.

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jsharris  19 Sep 2013 06:30 AM :

 In our case a soakaway wasn’t an option because of the close proximity to the stream. The feeling was that any soakaway would have been in “direct hydraulic continuity” with the stream (to use the hydrogeologists terminology) so would be little different to a direct connection. This was primarily because the treatment plant had to be just a few metres from the stream in order to keep it at least 7 metres away from any other building.

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ProDave 19 Sep 2013 07:44 AM :

 Interesting different rules.

Our treatment plant has to be 5 metres from a building or boundary but must be 10 metres from the stream, and that applies to the soakaway as well.

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jsharris 19 Sep 2013 08:07 AM :

 The difference in the rules is interesting. Here the building regs say this:

1.11 Packaged treatment works– This term is applied to a range of systems engineered to
treat a given hydraulic and organic load using prefabricated components which can be installed
with minimal site work. They use a number of processes which are different in detail, all treat
effluent to a higher standard than septic tank systems and this normally allows direct discharge
to a watercourse.

1.12 Packaged treatment works discharging to a suitable watercourse will normally be more
economic for larger developments than septic tanks. They should also be considered where space is
limited or where other options are not possible.”

which almost seems to encourage direct discharge to a watercourse!

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Shah 19 Sep 2013 01:05 PM :

 Excellent write up and share of information. Thanks a lot. This will make life easier for newbie like me

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TerryE  03 Apr 2015 10:30 AM :

 Jeremy, I’ve just downloaded this pack and Jan and I have gone through it because were at this stage ourselves now. Willie has given me a link to a tutorial on Draftsight (which is the AutoCAD compatible package that I use) which will help. This is really useful, so thanks for this. Two Qs though:

  • I noticed on your services drawing that you look your FW drain directly under the slab. Did you have any issues with this and at what depth did you run it?
  • I would have included a rodding access / eye at the rear of the house and taken the line directly across the house with a separate run from the kitchen gully trap to the inspection chamber, so the shit only meets the fat and kitchen washing in the chamber, and the run under the house is easily roddable. Did you do this in practice or was there any reasons for not doing so?

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jsharris 03 Apr 2015 11:36 AM :

The FW drain is a straight run from the swept bend at the base of the soil pipe vertical stack (which can be internally accessed from within the service space under the eaves if need be) to the 450 chamber in the path at the front of the house.

This means that I can rod from the chamber right up to the swept bend if it’s ever needed. I can also rod the short section from the kitchen trap to the swept tee in the main run of pipe very easily, as it’s only a short, near-vertical, length of pipe.

There’s no way I could add another rodding point at the rear of the house because of the retaining wall foundations, and I couldn’t see why there would be a need to get in at both ends of the foul drain, anyway. I don’t think I’ve ever lived in a house where it was possible to get at both ends of one that ran under the house, and I certainly can’t in our present house, that has a similar arrangement with the foul drain running party under the house to a vertical pipe that comes up in the WC, and then has the WC’s connected to it via above floor level pipes (which is what I’ve done with the new house).

I was originally going to have another vertical coming up through the floor for the kitchen waste, rather than have that go through the wall to an external trap, but could foresee two problems. The first was that access under the kitchen units was going to be a pain, the second was that I wanted to use the space under the sink unit plinth to fit the boiling water tap system.

Having the pipe go through the wall creates a small cold bridge, but the plan is to mitigate that by boxing around the external pipe in matching larch, with some insulation inside the box. I’m not sure it’s really needed, but apart from anything else it will make the pipe look a bit neater.

BTW, there’s no easy way to connect two parallel 110mm pipes to the bottom of a standard 450 pre-formed chamber as far as I can see, so a separate run from the kitchen gully wouldn’t have been that easy. Again it’s only a short run (maybe 5ft or so) and I can’t see any real issue with access via the chamber up as far as the swept tee, or access from the kitchen trap down to the swept tee below (and it is a fair way below, the drop from the kitchen gully trap to the run under the house is around 3 feet or so).

Building control were happy when they did the drains inspection, and remarked that it was nice to have just two long straight runs of pipe, so I assume that it’ll be OK. We’ve lived in some places with nightmare drain layouts in the past, including one with a sealed manhole under the middle of the living room fitted carpet!

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