A self build house project diary
by Oliver Cannell

Building our Eco knowledge at the EcoBuild show London

We visited EcoBuild this week to see which of the many Eco building products we could use in our development.

I'm not normally up for visiting big exhibitions like these, as they can be filled with a lot of eye-candy products, that are too expensive for my pocket, and you have to wade through a lot of sales waffle from companies trying to push their latest products. But for once, we had a real need to find out more about some of the products on offer, in the hope that we can make our new home more 'green'.

The show was held at the ExCeL centre in London, which is huge, so there were more than enough exhibitors to attract visitors from all aspects of the construction industry - designers & Architects, self builders, building contractors, eco-geeks... to mention just a few. There were three main zones in the exhibition - Sustainable Design & Construction, Energy and Future Cities - each of which housed stands by manufacturers, installers, retailers, organisations and educational establishments. There were seminars, live how-to demos, presentations and plenty of experts to help answer all sorts of questions.

Check out their website http://www.ecobuild.co.uk

In terms of our build, the house has been designed to use pretty much all standard building materials to keep costs to a minimum - non of which are classed as 'eco'. That is, apart from the Sedum Roof, which will help insulate the house, retain rain water without directing it straight down the drains, absorb the sun's heat without bouncing it back into the atmosphere and will help sustain the bees and insects in our the local enviroment. We would definitely like to get the Sedum Roof installed, but it's more like the icing on the cake as far as we can see at this stage, due to the tight budget.

When I originally asked the Architect to design the house, I wish, in hindsight, that I had asked for them to consider more eco friendly products in the construction. As we are now so far down the process - even though we haven't actually started building anything - it will mean additional costs and time delays to go somewhat back to the drawing board. Although time isn't a major issue for us... changing some of the products will mean changing the design of some elements (eg. wall thickness) and this will cost more in designer's fees and will likely also mean having to go back through the planning cycle.

Sedum Roof

This has always been an expensive element of our design and thankfully it will be done last, so we know it could be implemented a while after we move in. Although there is obviously no VAT to pay on new build houses, getting the sedum roof built now would be a lot cheaper than doing it later. However we have toyed with the idea of maybe doing it ourselves.

At Ecobuild there were a number of green roof manufacturers and installers. We spoke to a few of them to discuss what the options are and were happy to discover there are two systems available - one is referred to as "rollout" and one which is based on "trays". The rollout system basically means that all the layers involved (woven fabric drainage layer, growing medium, plants etc) are rolled out across the whole roof in one hit. This means the whole job has to be completed in one go. The "tray" system on the other hand, on offer from a few of the suppliers, are made up of 50cm square trays (about 10cm deep) which clip together. These are pre-loaded with all the required elements and they just clip together to make up the size and shape required.

We thought these guys were the most helpful and knowledgeable and would meet our needs the best. http://www.wallbarn.com/m-tray/


The manufacturer of cement is extremely polluting. For every tonne of cement made, there is almost a tonne of carbon dioxide (CO2) released into the atmosphere. The cement industry is responsible for approximiately 5% of the global CO2 output, so finding an alternative, like CemFree, would be a huge benefit if it could replace the use of traditional cement in the mainstream building industry.

I was hoping we could use something like CemFree, or a similar cement free concrete, but it will mean going back to the drawing board. However, we might be able to find some breeze blocks which have similiar thermal properties to standard blocks, which we might be able to use.


Wall Ties

Even the smallest of improvement to the components used in the build, will mean long term benefits, in terms of energy savings to run the house. Usually stainless steel wall ties are used in cavity walls, but there are now a range of basalt fibre wall ties available, which are 20 times less thermally conductive, which means less heat will be lost through the external walls.

Second Hand Building Materials

We discovered a small company running a website which specialises in helping people find batches of building materials, which have either been left-over from old jobs or are just excess stock. Although there is a lot of stuff like this on eBay, it's great to see a dedicated website providing an outlet for builders to sell their excess supplies and for self-builders to take advantage of some nice cost savings.

Check out the SurplusMatch website http://www.surplusmatch.co.uk

Green Paints

No, we're not intending to paint everything green - although I quite like the idea of have a section of grass-green flooring somewhere in the house. Natural paint is definitely the way forward, although they are less readily-available than normal paints and usually have a more limited range of colours.

So what's the difference? Standard paints may include ingredients such as formaldehyde, heavy metals and things known as Volatile Organic Compounds (VOC). These VOCs are gases which can have long and short term health effects and are emitted while actually painting - and for as long as five years after the paint has dried.

Here is an interesting article about Eco Paints (although from 2009) http://www.theguardian.com/lifeandstyle/2009/feb/09/eco-natural-paints-guide-best

Clay Plaster

Another more eco option is to use clay plaster, instead of gypsum based plasters or plasterboards. Instead of using a chemical reaction to harden, the clay is simply mixed with water and allowed to dry naturally. Plus, rather than setting hard like gypsum plaster, clay plasters can be moistened again with water and reworked where required. This is makes them much easier to tweak - should you need to - and very recyclable too.

We spoke to these guys at EcoBuild about what clay plaster products are available http://www.backtoearth.co.uk
Here is some great info about the advantages of using Clay Plaster. http://www.clay-works.com/blog/why-use-clay-plaster/

Solar Panels

An interesting aspect of our house design is that the shallow pitch roof, which will be covered with Sedum plants, and will be waterproofed using a Firestone RubberCover membrane. So we were wondering how, if in the future, we wanted to attach some solar panels to the roof, would we go about it without drilling holes in the membrane. We spoke to a number of solar panel mounting unit manufacturers to see what solutions they had on offer.

A few of them looked confused - as they are evidentally only used to mounting them to tiled roofs so far - but some of them had ballast-weighted mounting frames, which could sit on inclines of up to 10-degrees. This means they would just be held in place by the weight of the ballast and no drilling would be required. We just need to make sure the structure of the roof is strong enough to bear the weight.

These guys seemed to offer the best solution, from those we spoke with. http://www.k2-systems.uk.com

Kevin McCloud Seminar

Obviously we couldn't turn up to a show where Kevin McCloud is speaking, without going to see his seminar. After all, his TV show Grand Designs, is partly responsible for us doing this self build project in the first place!

The seminar was entitled "Better homes for less - can custom build, crowd funding and mutual home ownership solve the house crisis?" A very interesting topic and debate - one which I'll write a separate blog entry about soon.  :-)

Next entry: First concrete goes down (Friday 14th March 2014)

Previous entry: Nobody wanting to ‘tank’ responsibility (Monday 24th February 2014)

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