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Friday, 21 February 2014

Bay windows

Many older properties have attractive bay windows. However there is an issue that tends to go un-noticed by the great buying public. That of insulation in the bay. Basically there isn't any. The mullions and walls under the window are generally solid walls. This is not too much of an issue as the rest of the house will tend to be the same. However, insulating them is an issue to get right. However, this is the smallest problem. The main issue is that of the roof above the bay.

They tend to look a bit like this:

So there is virtually nothing between you and the outside world. A piece of plaster board / lath and plaster and then a void and the bay roof. So these structures are very draughty and not very insulating. So if improving an older property with a bay, this is one of the first things that needs to the addressed.

It is an easy (if disruptive) fix, as the installation of insulation is relatively simple and then it is a case of just making sure that the details are right. This basically means that you have to get the airtightness correct, so use good quality tapes and sealants to ensure that the final finish is well draught proofed.

Note that this situation can be mirrored under the bay if it is an 'unsupported' bay. These types of bays tend to be seen on more modern buildings and / or on replaced bays as they are cheaper. However, they are rarely sealed correctly and hence tend to be very draughty and again poorly insulated. Thankfully they also tend to be timber framed and hence are relatively easy to improve by using conventional insulation, membranes and good tapes.

If you are installing external wall insulation remember that the wall behind the bay also needs to be insulated to stop thermal bridging. Where the roof is tied into the wall will create a thermal bridge as well so think about how this will be dealt with.

Wednesday, 19 February 2014

Spot the Pigeon Problem

Where we are in Cardiff a local Housing Association has been busy installing PV onto their houses. Brilliant, just the ticket. The residents get to use the free energy created during the day, the HA gets the FiT payments and the planet gets a slight reprieve from a reduction in CO2 being pumped into the atmosphere.

There is though a slight issue that I noticed while glancing up at their handiwork. The clue is in the picture.

The workforce had installed the panels underneath an aerial, and being a seaside city we have a large number of gulls as well as pigeons. A nice secure aerial is a perfect place for a breather from scavenging the streets and whilst there, why not relieve yourself before heading off again! Consequently the areas, of the lovely new panels, below the aerials are covered with bird poo. This has a terrible effect on energy production, so all the benefits that should be accruing for the HA and tenants are being ruined by nature, just as we are trying to do something for it! So when designing your system think about factors like aerials so that you don't suffer this issue.

If you have PV fitted already, remember to check that they are clean and free from bird poo, leaf drop etc and also that any potential overshading issues are dealt with (for example the PV on our garage has a Wisteria growing on the wall next to it, so I have to cut back shoots etc during the growing season.)

Remember that PV is great for being 'low' maintenance, but it is not 'no' maintenance!

Wednesday, 12 February 2014

Egni Solar Co-Op Launched

Outside DOVE workshops

A hard working group of committed volunteers in SW Wales have been beavering around for the past year or so getting a large community driven solar PV project off of the ground. The Egni Co-Operative (see have clubbed together a wide range of community centres (inc the Dove Workshops shown above) so that they can 'borrow' their roofs in order to establish a community owned solar PV project.

The group had their official launch at the Welsh Senedd in early February 2014 and are now looking for community minded investors to reach their target. Investments range from £250 to £20,000 and operate on co-operative principles. See their website for more details on how the system works etc.

It is important that communities help themselves and it is great to see the SW Valleys communities doing just that, but monies for the project can come from anywhere as there is a return on offer. So have a look at the site and see if this is a project that you can support.

Egni Coop is also on twitter @egnicoop for anyone who is a keen twitterer.

RDE helped facilitate the non-domestic EPC work that was required for the project, so thanks to Iain at Greenfeet Energy Assessments ( with this.