Wednesday, 27 July 2011

Here it comes ... (Week twenty-five)

I don't know why but this is the bit of the build I've been most excited about. On Monday the solar panel installers from Rayotec ( arrived on site and here’s one of the panels that are now on our roof.

Over 1,000 watts of energy from the Sun hits each square metre of our planet every second, which means that every hour Earth gets enough energy for a year’s worth of human usage; a statistic that, frankly, makes my brain ache.  Our roof will make use of some of this energy to produce electricity and heat water. I mentioned the panels and tubes that are going on the roof a few weeks ago but now, as they say, here comes the science bit:

The solar panels make use of the “photovoltaic effect” which was discovered in 1839 by Edmond Becquerel. He noticed that some materials produce an electric current when exposed to light and this principle was explored throughout the 19th and 20th centuries by such luminaries (geddit?) as Einstein, leading to the development of things like solar powered calculators.

The roof panels look and feel like an aluminum whiteboard with an electrical connector on one side and on the surface (the blue side) they feel just as smooth but they are covered with thin layers of silicon.  Depending on how it is treated silicon can either be an insulator or conductor and here it’s been ‘doped’ so it acts as a semiconductor. 

When the sun shines on the panels the silicon absorbs the energy and releases electrons, creating a direct current across the layers. The stronger the sun and the greater the number of panels the more electricity you create and, as you see from the photos we have 28 panels. There’s a neat graphic of how they work from the energy savings’ trust.

By the ridge in the middle of the roof we also have the tubes for the solar thermal system. The tubes are designed a bit like a vacuum flask with two layers of glass and a vacuum between them. Under the tubes there’s a mirror, which helps maximise the amount of sun they receive  and the inner tubes are treated with Aluminum nitrite which absorbs sunlight and converts it into heat energy. Full details are available on the manufacturer’s website.

So, during daylight, we ought to be self-sufficient with our electricity and on sunnier days we will be merrily farming electricity. The environmental impact of the whole system is equivalent to taking three cars off the road, which doesn’t sound like much in the great scheme of things but it’s a start. Anything we can do as individuals to reduce climate change has got to be good.

Saturday, 23 July 2011

End of week twenty-four


It was a bit tricky finding my usual spot for the first picture this week because, as most of the photos show, we have stacks of the latest building material everywhere.
These are the insulation blocks that will be stuck to the outside walls. They are 1m x 50cm in size and 25cm deep and made of expanded polystyrene. If you click here there's a picture of how they'll be installed and here's the manufacturer's brochure. The boards will work like one of those jackets that ensure water in a hot water cylinder retains its heat. The house will look extremely peculiar when they are first put on but this won't be the final finish.

Indoors the walls are still being plastered and the acoustic insulation that was being stuck round the bottoms of the walls is now appearing on the floor too, which makes a bit more sense.

And, of course, the skeleton of the porch (picture 2 above) is being added too with the thickest wooden uprights this side of a telegraph pole. I've been seeing drawings of the porch on the plans but, somehow, I never connected with how big it is.

Next week, all being equal, the solar panels appear which is something I've been really looking forward to. It's now less than two months to go.... so exciting!

Friday, 15 July 2011

End of week twenty-three

We should only have seven weeks to go now, although it looks like the build may over-run slightly.

The roof on the south side is slated and if you look on the bottom two pictures you can see the beginnings of the bay window on top floor for the first time.

The plasterers are still hard at work inside and this view of the top floor (left) shows how things have changed from last week.

The rooms on the middle floor are getting this yellow lining at the bottom of the walls. It's acoustic insulation which will reduce how sound travels between floors - always a plus in a house that doubles as both a home to a noisy family and office space!

Wednesday, 13 July 2011

Advert break 2: Save our butterflies

Can I encourage everyone to take part in the Butterfly Conservation's "Big Butterfly Count" between 16th and 30th July this year?

Many butterfly species in the UK are in decline as a result of the damage we are doing to the environment so please spend 15 minutes in the next few weeks logging butterflies in your area and sending the results in.

And if you have a garden, shove in a buddleia or verbena bonariensis somewhere and make a butterfly happy.

Here's some pics of butterflies from our garden last year, this year there are hardly any.

I hope the massive decline this summer is simply due to sharing the garden with Bob the Builder and his team.

PS: Round of applause to Darsham for their new butterfly reserve!

Saturday, 9 July 2011

End of week twenty-two

Externally the site doesn't look so very different, although some more slates have appeared on the roof.

At the beginning of the week the stairs arrived on site. 

Here they are before being installed....

... and here's where they were by the end of the week  (the white covering is cardboard to protect the stairs during the build).
The other major change has been that the walls are getting plastered. 

The plasterers are making a fantastic job and the rooms seem much bigger than they did when you could just see the concrete blocks.

This room is the kitchen; there will be another photo when it's complete.

With the stairs in place it's now possible, with a bit of agility, to see the rooms on the top floor and here's a picture of all the membranes that are making the roof airtight.

The insulation that was installed last week was pumped behind the membranes which is why they look a bit sagging in places. It's has been put in at a depth of 400mm so the upstairs is both well insulated for warmth and amazingly sound-proofed too.

The thing that looks like a black hose in the foreground is the cabling for the thermal solar panels that went in a couple of weeks ago.

Sunday, 3 July 2011

End of week twenty-one (nine weeks to go?)

There have been a lot of changes to the site this week:


Externally the roof hasn't changed much but the footings for the porch have been built and inside the door frames are in place and the wiring is now set into the walls.

Towards the end of the week this van appeared with the insulation for the roof. The two tubes ran from the van to the house and for almost the entire day it pumped the insulation into the roof. If you ever wondered what happens to newspapers and unwanted paperback books that end up in recycling here's your answer. 

The insulation looks like the mashed up paper filling that you sometimes find in padded envelopes and the manufacturers are based in Wales. 

It's nice to think of unloved books being turned into something worthwhile - you won't be able to do that with your e-book readers, will you?

In the garden yet another hole has been dug and that's for the rainwater harvester. This will collect water from the roof and reuse it to flush the loos. As it has hardly rained here since the build started five months ago I have checked what will happen when the harvester runs dry and I'm pleased to see that we will automatically switch over to mains water when that happens.

A close-up of the harvester shows how it gets connected up (it's very technical!). The pipes will go in soon and there's a photo in the entry for the  first week to show where the recycled water will enter the house.

If you want to read more about how the harvesting system works you can look at the manufacturer's website. In the meantime here's a photo of the unit before it was buried, it's just under 2m tall so that's another deep hole under the garden.