Glass for the fish bowl has arrived

The Yprado GRP window frames and doors, with the glazing has arrived.

2014-01-23 10.45.50 (2) The rather large truck stayed down the road and the forklift cherry picker brought the pallets up to the house:

2014-01-23 09.52.16 (2)

The ecofab team are packing up areas that didn’t have panels with sheep wool (bundle below) and starting to put sealing tape for, what will be, an “airtight house”.

2014-01-22 08.57.23 (2) The rear external stair cast concrete steps are in:

2014-01-22 09.10.07 (2) From the beach, the house has it’s form:

2014-01-19 08.06.41 (2)

Dawn moon over the sea: 2014-01-19 08.06.33 (2)




£50,000 printed house released by WikiHouse


Looking at the details in the PDF, a lot of the ideas are similar to those being used by ecofab for my project:
– see some screen grabs below.

From the article:

WikiHouse has released the design for a £50,000 printed house for the UK that could help tackle problems like urbanisation, climate change and inequality, say creators.

The design is the latest creation from the non-profit project that has been developed to help produce low-cost, high-performance houses that are suited to local needs.

The project, called WikiHouse, is an open source construction system which makes it possible for anyone to design, share, download, adapt and ‘print’ houses.

Users of the system can ‘print’ house parts from a standard sheet material like plywood, and the main structure assembled in about a day without the need for conventional construction skills, say creators.

“The open secret is that in reality almost everything we today call architecture is actually design for the 1%,” said WikiHouse co-designer Alastair Parvin of London-based design studio 00.


“The challenge facing the next generation of architects is how, for the first time, we will make our client not the 1% but the 100% – to radically democratise the production of architecture.”

He added: “We are moving into a future where the factory can be everywhere – and increasingly the design team can be everyone.”

WikiHouse is currently under development, with a growing community of teams and is seeking collaborators and funders.

Wall panel layers:





Assembled wall panel:

YPRADO GRP Windows and Doors

This week, one of the senior chaps from YPRADO came to the ARCO2 / ecofab offices to do a presentation on the YPRADO company and their Pultec®  GRP Windows & Doors.

Great to see a full sample window and a corner cross section.

GRP goes under several names:
GRP = Glass Re-enforced Plastic = Fiberglass Reinforced Plastics (FRP) = composite

Great to have the presentation and then discussion with Chris Dixon from YPRADO and the ARCO2 ecofab team.

  • Manufacture.
    • The GRP is pulled through the pulleys etc. The even and controlled drying out / curing of the GRP means that if damaged (like a GRP surf board) you don’t exposed glass fibres and un-cured resin that can give osmosis star crazing.
  • Maintenance needs (super low, just the metal hardware)
  • Lifespan (75 years plus, ease of replacing any glazing units that fail).
    • Outlasting PVC, Alu clad wood etc. means ends up being cheaper and lower environmental impact as one set of GRP windows and doors = 1+ sets if PVC, wood or Alu clad wood.
  • End of life recycling (theoretically possible, but nobody is currently doing this, but how much are Alu clad timber frames etc. properly recycled? Sadly, few if any).
    • In Europe their seem to be only 3 factories who can recycle GRP. ERCOM in Germany, MCR in France and Miljotek in Norway. They struggle to find markets for their recyclate.
    • Current end of GRP life is landfill (relatively cheap), incineration (50% becomes ash which is landfilled) or into cement production (energy from incineration and ash into the cement).
    • There is currently no market value for waste composite in the UK as recyclate. Other than a few firms which grind production waste and use it as filler. At the moment the recycling cost is too high. As the price of landfill goes up or the raw material price goes up, this could change.
  • Cost.
    • Outlasts alternatives, so over 30 years apparently cheaper than PVC.
    • Wood required re-painting every 3 or so years. Factor that cost in and the shorter life and more expensive.
    • Initial outlay can be lower. Current GRP quote from Pultec is a LOT less than the quote for Alu Clad wood doors and windows (that don’t have as good a thermal U-value !)

Photo of the sample window brought to the meeting. Focusing on the handle!

YPRADO - window handle

Pultec GRP Windows Specification

  • Triple glazed
  • Krypton fill
    • Argon has a thermal conductivity 67% that of air,
      krypton has about half the conductivity of argon.
    • Krypton is an inert gas, heavier and denser than Oxygen. It is colourless, odourless, tasteless and harmless. The Earth’s atmosphere is made up of approximately 0.00011% krypton. It is obtained by separating air into its constituent components by fractional distillation.
  • Warm edge spacers
  • Double Low ‘E’ softcoat.
    • This metal coating reflects heat (keeping heat in during the winter and sun heat out in the summer)
    • Soft coat Low E glass is more reflective than hard coat Low E glass.
    • Soft coat Low-E glass,  involves the application of silver, zinc or tin to glass in a vacuum. The glass enters a vacuum chamber filled with an inert gas which is electrically charged. The electricity combined with the vacuum allows molecules of metal to sputter onto the glass. The coating is fairly delicate or “soft.”
    • A “hard-coat” low-e application is done when the glass is in a molten state. The process results in a durable coating that can be used on storm doors and windows. A “soft-coat” low-e application happens after the glass is made. The soft coat is more efficient at reflecting heat energy, but also more delicate. This low-e coating always faces the insulating airspace in double or triple-pane glazing. Since soft coat emissivity can oxidize when exposed to air, argon or krypton gas is often used in the insulating airspace to help preserve the coating.

Summary of advantages of GRP Windows:

This summary is from an email from YPRADO.


  • “A” Rated in BRE Green Guide to Specification for Sustainable Construction (UK)
  • BREEAM: 4½ extra credits potentially available.
  • 22% is from a recycled source. Product 100% recyclable upon disposal.
  • 65% glass content, (silica/sand, the most abundant substance on the planet)
  • Sensitivity Report (emailed to me), quantifying environmental credentials by sustainability consultants Price & Myers, London.

Energy Efficiency:

  • “U” values 0.8 – 1.6 “U” W/M2K on the total window. 1.2 U value achieved with double glazing only, no need for triple (thus cheaper and less wear on hinges)
    • I’ve asked for triple glazing, so even better U Values.
  • Low embodied energy in pultrusion manufacturing process (confirmed by GreenBuildingForum threads, where there was however some discussion regarding the embodied energy of the raw materials).


  • Twice the strength to weight ratio of mild steel – cannot deform like aluminium
  • 75 years service life + 12 year Warranty.
  • Negligible coefficient of expansion, even if coated black
  • Performance unaffected in temperatures between +100C and -100C
  • Impervious to UV degradation
    • But the paint will slowly fade in colour.
    • The paint is over the white GRP frames. The paint chemically bonds to the GRP (unlike paint on Aluminium frames).
  • Impervious to salt corrosion and sea water.
  • Impervious to the harshest weather – effectively, indestructible by natural forces.

General performance:

  • Robust! – used on Young Mental Offenders Secure Units – Meets MOD anti-terrorist glazing requirements – DMG2 “Normal”
  • Secured by Design accredited – Police preferred specification – including both BS 7950 and PAS 23/24
  • Zero maintenance required – however, surface damage, structural repairs and re-painting can be easily undertaken on site, with no consequential liability for future applications.
    • You can just use surf board resin or similar.
  • High resistance to impact damage – will not deform under impact.
  • Highly price competitive with aluminium and timber/alu composite windows.
  • Any RAL colour available (200+ options)
  • Impervious to all chemicals and most acids.

Thermal Scanner

There are a lot of conversations on the GreenBuilding Forum:

That include using a thermal scanner for during and post build use of thermal scanners to check for thermal efficiency (leaks, bridging, U-values).

Wait for the heating to be working, so that it’s warmer inside than outside by 8C or more (so probably winter !) and start using a scanner.

From inside, to look in all directions (floor, walls, ceiling) and from as many external aspects as you can. You could find where (for example) insulation in the wall has perhaps sagged and left a less insulated section.

Yes you’ll possibly find problems when it’s too late (ie not during the build) but better late than never, as you may still be able to improve where these problems are.
– if it’s during the build, but post final hand over, you can get the builder(s) in to sort out the problems.

It’d also be interesting to 2, 3, 5, 10, 20 years on to do the same and see how the building has held up.
– yes it’d be good to also get an air test several years in.

Cost Implication / Problem

One problem with this plan is that an air test is about £300 at the moment. That’s a lot, unless you believe there is a big reduction in the building efficiency and you want to check, to confirm (and if the case) resolve what has failed over time.

FLIR Thermal Image cameras start at around £1,000 and what training / learning do you need to use one properly?


FLIR i3 / i5 / i7 camera model comparison


 FLIR i3 FLIR i5 FLIR i7
Thermal image quality:
60×60 pixels
Thermal image quality:
100×100 pixels
Thermal image quality:
140×140 pixels
Field of View:
12.5°(H) x 12.5°(V)
Field of View:
21°(H) x 21°(V)
Field of View:
29°(H) x 29°(V)
Center spot Center spot Spotmeter, area with max./min. temperature, isotherm above/below
Thermal sensitivity: 0.15°C Thermal sensitivity: 0.10°C Thermal sensitivity: 0.10°C

Net Zero Vs Passivhaus


 in Passivhaus, you want to put in so much insulation and such high quality windows that you barely need to heat or cool at all, minimizing energy use; In Net Zero, you want to generate enough power on site to heat, cool and light your house; it could be a draughty barn,

OK, with the proviso that the cost (actual and environmental) of creating an insulated and well sealed house is sensible, this gives a long term resilient property, that should be liveable  even if the power generation systems fail.

I’m with the bias being a super insulated and sealed house first and then minimum tech to supply on-site power (elec and heating).

Initial SAP Calc’s look great

Although the project is a long way off being ready for a full and final SAP Calculation (SAP background and definition below) I wanted to put the planned building, with the current details, past an experienced SAP consultant to see where it comes out.

This meant that for a lot of figures, there are assumed values, which are a lot worse than the planned values.

For example the SAP calc’s used a figure of 4.0m³/m²/hr at 50Pa.

  • The aim is a target air permeability of 1m³/m²/hr at 50Pa.
    (Current UK Building Regulation Standard is 10m³/m²/hr at 50Pa.)

Even with these default values, the house exceeds current UK requirements.

The initial value has come out as 74 and an emissions (t/year) figure of 5.53.
Adding in the planned 4KW PV system gives figures of 82 and 3.71 (respectively).

That is an annual saving of 1.82 tonnes of carbon. This highlights the level of carbon created at generation (power plants) and the transmittal loss to point of use, PV removes this element and has such a positive affect in reducing CO2.

The SAP consultant (Grant Williams, Tel: 01249 650051) was also able to give his general feedback:

The thermal values issued by ARCO2 are as good as I get to see in all of my clients ….

You seem to be on top of the project with regards to the air tightness this is very refreshing as a vast number rely on mastic post construction.

Also you are very aware of the importance of the thermal bridges I have entered a standard figure for this at a Y Value of 0.08 however if someone has completed the calculation I can alter this at a later date.

The final rating will be improve upon just by issuing the make and model of the Ventilation, Boiler and Closed Log Burner as I have used default figures which are at the bottom of the required efficiency to pass the Compliance.

Standard Assessment Procedure (SAP) calculations show details of the Target Emission Rate (TER) versus the Dwelling Emmission Rate (DER).

To be comparable for all properties, the SAP rating is adjusted to floor area, so that it is essentially independent of dwelling size. It takes into account the following range of factors, which contribute to energy consumption:

  • Thermal insulation of the building fabric.
  • Efficiency and control of the heating system.
  • Ventilation characteristics of the dwelling
  • Solar gain characteristics of the dwelling
  • The fuel used for space and water heating

SAP has been adopted by government as part of the UK national standard for calculating the energy performance of buildings.

Every new house has to have a SAP rating.  It provides a simple means of reliably estimating the energy efficiency performance of your home.
SAP ratings are expressed on a scale of 1 to 100 – the higher the number, the better the rating. Thus it is similar to the fuel consumption of a car under standard driving conditions. SAP is calculated by a procedure which is specified in Building Regulations, and which predicts heating and hot water costs.These costs depend on the insulation and air tightness of the house, and on the efficiency and control of the heating system. The calculation uses the Building Research Establishment‘s Domestic Energy Model (BREDEM).
The ecofab panels and general construction has:
  • Floor, walls & roof are all the same box panels with 0.12 w/m2K U-Value (or better)
  • Air permeability target is below 1 m³/(h.m²) @ 50 Pa

SAP calculations (Air leakage, U-values & thermal bridging)

As we head towards sending in the planning permission (we’ve had 2 positive pre-planning meetings), the design has been sent for a preliminary SAP analysis.

A fundamental objective is to create a thermally efficient building, so that over it’s lifetime, the amount of energy to keep the interior at a comfortable temperature and humidity more than offsets the cost (money and environmental cost) to achieve this efficiency.

In crude financial terms, the cost of heating an uninsulated house is nearly three times that of heating a modern well insulated property of the same living area.

Heated buildings loose energy in 3 ways:

  1. Air leakage through holes (hence an airtest and an “air-tight” building).
  2. Through the fabric of the building. The u-values of the materials measure how much heat is lost through them. This is primarily the walls, floors, windows, doors and roof of the building.
    The lower the U-value, the better that section of the structure. For example, a wall with a U-value of 1.0 will lose heat twice as fast as a wall with a U-value of 0.5.
  3. Through the cold bridges between the different elements. These are the Ψ (psi) values.
    – “Thermal bridging occurs where the insulation layer is penetrated by a material with a relatively high thermal conductivity.”

The SAP assessor will look at all of these. They will multiply the Ψ (psi) values by the total length of their construction in the building to get a y-value. The y-value is analogous to an aggregated u-value for all the junctions in the building.

What y-values are used in the SAP calculations can have a big impact on the end figure.


  1. SAP assessor can use default value of 0.15, or
  2. Calculated value using the Ψ (psi) values listed by the Building Regulations for Accredited Details (normally 0.8 or higher, or
  3. A calculated value using thermally modelled junction Ψ (psi) values, which can come out as low as 0.04 depending upon construction details used.
The difference can, apparently be the equivalent of an open garage door on the side of the building ! (best to worst).

Recycled Foamed Glass Insulation

28 May 2012 Update:

I put a post on and the consistent reply is that it’s more expensive than well used and well know Leca, which is usually used with a breathable Limecrete floor. I’m not sure if it’d work / work as well under a non breathing floor.

I was at a Green Building show / expo / day at the Eden Project last week and there was a talk by a German sounding chap, who is part of the UK Epoc Europe Ltd team promoting / pushing their TECHNOpor (Recycled Foamed Glass).

The key points seemed to be:

  • uses 100% (or close to 100%) recycled materials (glass bottles etc.)
  • German factory is powered by HEP electricity.
  • light to transport on low emmisions trucks from Germany.
  • easy to work with.
  • good insulation values for under the floor, behind retaining walls.
  • can even be used for between floor and in ceilings insulation (as super light).

I’ve found 2 UK Websites related to this:

The German site for TECHNOpor is

The Swiss site has a great idea of using bags for when you use the Recycled Foam Glass to insulate a wall. Given that there will be 2 retaining walls, this could be great.