We have just bought an old farmhouse and are currently ripping down all lath and plaster walls to insulate - see our blog if you'd like (address below).
I'd strongly advise external wall insulation. It works better as you end up with your walls as a thermal mass on the conditioned side.
Internal insulation will make the rooms smaller, it will leave you with permanent problems with fixing things to the walls, with de-rating cable capacities due to thermal insulation and with the challenge of maintaining a vapour seal where you sink back boxes and pass cables and pipes through (because if you don't do that you'll get condensation on the cold walls which will lead to mould growth. Maybe even mushrooms.)
We have to re-wire too so now is the time to get creative with regards to electrics. I am planning to have some kind of circuit so that I can switch on all lamps from one switch at the door.
All of them?
Why, and how would that work? Assuming that you'd also want to switch them in the rooms they're in how would you know if they were already on if you couldn't see them, and if therefore the switch by the door was actually turning them off? And it would mean a lot of wiring unless you went for radio control or the complexity of some kind of automation.
Mind you - a lot of people are anal enough to want precisely repeatable settings of light levels and lazy enough not to want to get up and walk to a switch for their to be a market for both of those. Just avoid X10 like the plague.
One of the regulars here has a site where he describes his automated lighting system in detail.
Think hard about where to have sockets - it's difficult to have too many, and also about what circuits to have. The items on the list below won't all apply to you, but they are worth thinking about:
- Upstairs sockets
- Downstairs sockets
- Kitchen sockets
- Circuit for appliances
- Cooker circuit
- Non-RCD circuit for F/F
- Non-RCD circuit for CH boiler
- Dedicated circuit for hifi
- Dedicated circuit for IT equipment
- Upstairs lights
- Downstairs lights
- Lighting circuits with switches in the usual places but with 3A/5A round pin sockets at low level.
- Immersion heater
- Loft lights
- Shower
- Bathroom circuit
- Alarms
- Supply for outside lights
- Supply for garden electrics
- Supply for shed/garage
Plus any peculiarities brought about by your house layout & construction - e.g. in mine because of solid floors and where the socket circuits run, I have a radial just for a socket in the hall, the doorbell and the porch lights.
Unless you want to go to the expense of RCBOs throughout, the CU should have at least 3 sections, 2 on RCDs and one not into which you can install a mix of RCBOs and MCBs.
It can be a good idea to put all wiring in conduit for ease of future changes. And if you specify metal conduit for switch drops, or BS 8436 cable it removes the need to have RCDs where you'd rather not.
If you live somewhere where supplies are dodgy in the winter, have the lights, the boiler supply, and a socket in each room wired to a separate CU, or a separate section in a large one, that can be supplied by an emergency generator - lights, heating, TV and a kettle/microwave make life a lot more bearable.
Flood-wiring with
Cat6 or Cat6a cable is worth thinking about.
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The plan here is to dig out some of the earth, and then lay a concrete foundation on which the joists will sit (with a damp proof course in between). "
No insulation?
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However, we plan to replace it with a concrete lintel. "
Concrete is very "non-green".
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The heat source will be from an air source heat pump"
If you've got the space, and are turning the place into a building site anyway, wouldn't a GSHP be better?
And you really should think about some kind of backup heating for when the electricity goes off.
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I don't think there is one surface throughout the whole house that is dust free!"
You'd better get used to that.....
