Buying An Empty Shell

[JohnB]

I'm looking at a small stone 2 bed semi-detached cottage on Saturday. It's supposed to be structurally sound, but has had all external render and internal plaster removed, presumably as part of an abandoned renovation. This seems ideal to me as it gives me the chance to do my own thing with it.

I would like to use lime, and add insulation, external if possible. Can someone give me a rough idea of the cost per sq metre for materials and suitable breathable insulation? I would like to learn to do the plastering myself, but would need expert help, so would like a rough idea of labour costs too.

In an ideal world I'd buy some land and build a low impact house myself, and my aim would be to turn this cottage into a low impact home with minimal "green" gadgets. This seems more practical than the new build option as it avoids a big battle with the planners. If the house is structurally complete, am I likely to have much trouble with planners or building control?

Sorry this is rather vague, but I want some general idea quickly as I think I may need to make a quick offer after I've seen it.

 

[Mark]

First question would be why has it had a renovation started then abandoned? I'd be looking hard for hidden problems - either legal/planning or structural.

Talk to the planners for info on how they would view external insulation with render over. (Is it in a conservation area or listed or anything?)

There are tables giving costs for materials/labour to renovate to diff standards in diff areas of the country. A ballpark figure might be around £500/m2 (of floor area) upwards (Talking on some of the French forums figures between €750 - €1500 are being bandied around and that tends to be using lime and fairly green). I know that sounds a lot but by the time you add up flooring, roofing, insulation, plaster, electrics, plumbing, etc then you are putting a lot of cash in. And Green often means expensive although obviously you can bring costs down by DIY. But costs do grow fast.

Have a look at the AECB forum and the greenbuilding forum.

I should say that Im not a pro - just an interested bystander.

 

[Penners]

I certainly echo Mark's comment about the abandonment of the previous reapir/renovation attempt. You need to be quite certain that there are no skeletons in cupboards (probably an inapt metaphor, since there are no cupboards).

As to estimating the cost of your plans, I think you'll need to start creating a rather more specific list of your intentions before that begins to be possible. If you want to be as green as possible, will you for example be considering such things as ground-source under-floor heating, a wind turbine, photovoltaics, grey water storage... and so on? Each of these brings pretty substantial cost implications, which could make a dramatic difference to overall costs.

Provided the building isn't listed, or in a conservation area, my inexpert opinion is that you shouldn't have too much trouble with planners over such things. However, something like a wind turbine can stir up a fair amount of opposition among neighbours.

I can't comment on the cost of your lime plaster work. But are you sure that external insulation is necessary? A number of lime experts have mentioned on this forum that lime plaster does have a positive insulation effect, although I can't remember whether that's ever been quantified.

Hopefully others will give you a more expert view.

 

[Essex]

Please, please think carefully about renewables. Ground source heat pumps use electricity and as electricity needs approx 2.6 units of primary energy (gas, oil) to produce energy they are not necessarily any more carbon efficient than using gas or oil with an efficient condensing boiler. You need to know what the efficiency is in use, not the claimed efficiency from calculations as it can vary considerably. Wind turbines need space and height (30m away from any obstruction like a tree or a house for example) and should be on the west side of the country to get enough wind. If you get a wood pellet boiler you need a reliable source of, preferably local, pellets, something that is not always available everywhere in the country.
Insulate, build tight and ventilate right (appropriately for historic buildings) should be your priorities, and then your power sources.

 

[Penners]

I'm sure Essex is right on a number of points, but the wind turbine constraints seem a bit awry.

Here in deepest, far-eastern Suffolk, there's a 6kW wind turbine at the pub just down the road. It's a respectable distance from the nearest trees but I wouldn't have said 30m. And despite being in the east of the country, there are very few days when it isn't turning (I walk the dog close by almost every day).

 

[Essex]

There is a difference between turning and being efficient. A site with a good wind resource will have an annual wind speed of 7m/s at 25m above ground level. The government database on wind speeds is a good starting point http://www.dti.gov.uk/energy/sources/renewables/renewables-explained/wind-energy/page27326.html.
My windspeed, on top of a hill in Essex is only 5.2m/sec at 10m and 5.9 at 25m. (I don't think a 25m turbine is practical for one house). A lot is claimed for turbines, particularly by people with a vested interest in selling them. My recommendation is be careful and do your homework. The Centre for Alternative Technology is a good resource.

 

[Mark]

I'd agree with that. Ive seen some very optimistic claims on wind turbines, but v.little in the way of real evidence of sensible performance and payback.

 

[Penners]

There is a difference between turning and being efficient.

Can you expand on this? Clearly the speed of rotation affects the output of the unit - do you know what the typical rotational speed must be to achieve the unit's optimum rating (in this case 6kW)?

We're at one of the highest points in Suffolk (the air's very thin up here :wink: ) and to my inexpert eye, the turbine in question is frequently rotating at a good lick.

 

[MdB]

Proper wind turbines turn at a constant speed. I'm not sure what toy turbines do but it they are likely to be similar as high speeds causes more wear / noise.

Rough figures for proper wind turbines:

Start generating at 5m/s

Optimum speed is 15m/s -> produces 27 times the amount of electricity compared to 5m/s (cube law)

Shut down speed is 25m/s

 

[Penners]

Does a 6kW count as a "toy"? To my uneducated eye it seems quite a respectable specification for a privately owned unit.

 

[Essex]

I would imagine that the turning speed is dependent upon the gearing, weight, design etc of the turbine, which would be dependent upon the manufacturer. I know of a turbine in Hertfordshire, which, although it turns splendidly most of the time, is only 20% efficient, which is not good.
My understanding is that the critical factors are location, wind speed at the location, height of the turbine above ground level and the efficiency of the turbine itself. You might care to look at the DTI site I mentioned in a previous post to find the wind speed for your location. Generally though, although we are the second windiest nation on the planet, the wind speeds to the west are greater than to the east.
Turbines are more effective at small community and above scale.

 

[Penners]

Your useful link above has been changed, I'm afraid. It's now:

http://www.dti.gov.uk/energy/sources/renewables/explained/wind/windspeed-database/page27708.html

Windspeeds here are cited as 4.9m/s at 10m and 5.7m/s at 25m. The turbine at the pub is 19m high. They applied for permission to make it 25m high, but this was turned down in favour of 19m.

So, by extrapolation, I imagine they're getting a wind speed of around 5.4m/s.

 

[MdB]

Proper => Takes less than 12 months to generate the amount of energy that was required to make it. i.e. it will reduce the amount of oil we currently use.

Toy => Takes great than 10 years to generate the amount of energy that was required to make it. i.e. its production is a drain on our oil usage for a typical life.

(large wind systems typically take 9 to 12 months, coal / oil power stations typically take 6 months)

 

[skier-hughes]

Jane Smith has a wonderful turbine, do a search for her and turbine and I'm sure you'll find her comments very useful on actually living with a turbine.
It's large, turns slowly, is quiet and produces enough energy for allher needs.
She lives in the middle of the country, but it is on the top of a very big hill, in a magnificent place!!!

Graham

 

[Essex]

Interesting about the website as I copied it from the webpage an hour ago???

 

[Essex]

Back to the original question. Have a look at hemcrete for insulation

 

[Penners]

Proper => Takes less than 12 months to generate the amount of energy that was required to make it. i.e. it will reduce the amount of oil we currently use.

Toy => Takes great than 10 years to generate the amount of energy that was required to make it.

While I can clearly see the substantial difference, I suppose the missing factor from the above is the useful working life of the turbine.

If the "toy" crumbles to dust after 10 years, then it's pointless. But if it's still generating after 20 years, surely it has some validity, albeit not as much as the "proper"?

 

[MdB]

True of course but I doubt the toys have an average life of five years let alone 10 years, not that I have any figures. Time will tell.

 

[Flyfisher]

I know of a turbine in Hertfordshire, which, although it turns splendidly most of the time, is only 20% efficient, which is not good.

Presumably, the 20% figure is a percentage of the maximum potential output but I'm not entirely sure why this is 'not good'. Extracting 20% of the potential energy from oil or gas would definitely be 'not good' but when the energy source is unlimited and renewable surely any percentage is 'good' ?

The 'turbine in Hertfordshire' isn't the one near Watford and visible from the M25 is it? It belongs to a renewable energy company but I read recently that there is a campaign to stop anymore being built in the area :roll:

Meanwhile, the commercial Ecotricity wind farm near us at Swaffham seems to be growing all the time, well over half a dozen of things so far, so it must be economically feasible to build them in the east and not just the upland regions.

 

[Mark]

economically feasible

But that isnt neccessarily feasible on other grounds