Thursday, 27 February 2014

Warm work - home insulation

The work described here is part of package of measures being embarked upon, to reduce heat loss from a 1960's semi-detached house in Frome, Somerset. The work has been jointly designed by myself and Paul Buckingham - we are both graduates of the Centre for Alternative Technology Architecture course Advanced Environmental and Energy Studies (PG Dip/MSc).

Top left shows roof plate of my 1960s semi-detached house - uninsulated and with a large area of cold wall inside above all the top floor windows. This is where condensation occurs and mould grows - a problem with all the 1960s houses built to this design.(See my post Save before Generating for more on this.) Windows are below the soffit boards at the base of the roof. Battens attached to the outer blocks support the soffits. The top row of outer blocks is has been used to close up the 50mm cavity.

The picture to the right shows the party wall with an uninsulated cavity that is exposed to the cold where it joins the roof - a major problem. To address it will require pumping insulation in via the internal wall or taking all the roof tiles off to expose and fill it that way. We are exploring the possibility of insulating from inside but have yet to find a company willing to do it. They seem to be few and far between.It is mad that if cavity wall insulation is done (often under a government grant scheme - now it is free to anyone) the party wall is not. As a consequence, this type of house will have only one brick skin between the internal part of the property and the cold winter air.

100mm polystyrene insulation has been used - cut in steps up to and including the first 500mm into the loft space. Loft insulation has then been overlapped. An air gap has been left to allow for air to circulate in the roof (inflow via vents in the soffits). Ventilation - moving air - in the roof is vital to prevent condensation occurring in the loft. A section of roof felt had to be replaced with a suitable membrane, although we were able to reuse the battens for fixing the tiles.
Vermiculite was used to fill in gaps between the steps of insulation. The insulation sytem used is Knauf-Marmorit - 100mm polystyrene stuck down with a lime-based mortar (also used to insulate the rear exterior of the house). The down side of this system is the huge quantity of polystyrene waste, and the impossibility of controlling where all the bits go. Despite our best efforts, there are bits of polystyrene all over the place in the garden. With hindsight I would in future prefer to use a wood-fibre product - much more sustainable and environmentally friendly (although nowhere near as good an insulator).

Cavity wall insulation
The house was cavity-wall insulated in 2008, but we know that the insulation did not reach many areas, including under windows and beside doors. Thermal imaging of other properties has shown that insulating cavity walls, especially those with 50mm cavities, is not an exact science. However, leaving bits of uninsulated walls means small areas of cold surface where condensation will readily occur. I have begun the process of seeking restorative work on my property by the company responsible for the insulation - there is a 25-year guarantee.However, they don't seem to be able to find contractors to do the work, as yet.

Sunday, 2 February 2014

Flooding and farming: level heads are needed

Feelings are running high in Somerset as parts of the Levels continue to be inundated with deep floodwater, causing untold misery to those who live and farm there. Locals are convinced that some river-dredging would have substantially reduced the length of time the land there has been underwater and offer evidence from the Environment Agency demonstrating this. The EA did start some dredging last year at 'pinch points'. I suspect the work was delayed owing to the incredibly wet summer - a lot of land-related contract work just didn't get done in 2012 - a large area of the Levels was flooded at the time.

There's a lot to consider about how the Levels should be managed, and the debate needs to cover all bases, not just be confined to dredging. However, to date there hasn't been a rounded debate - and this is badly needed. It is vital to look at reducing the quantity of silt being eroded off farmland into the rivers - after all it is a first principle in addressing pollution control to deal with SOURCE before PATHWAY and finally RECEPTOR. Catchment Sensitive Farming initiatives aim to help farmers with this, but the initiative is inadequately funded (our R Frome initaitive is to be put into ''passive" status owing to inadequate funding) with CSF "struggling" to deliver.

In all the years I have been working in land management, many daft things have been done to floodplains and high up on the list is the conversion of permanent pasture to temporary grassland or, worse still, arable land in areas which should NEVER have been ploughed. One of the daftest examples was the construction of an embankment within part of the Nene Washes (Cambs) within which the land was pumped and carrots grown (the water being pumped on to adjacent land, making that wetter!) The Washes were designed to TAKE AND HOLD FLOODWATER and should never have been used to grow arable crops. This daftness was eventually put into reverse, but Tory MP Richard Body was one of many commentators who raised the profile about this type of mad subsidy-driven farming in his books Agriculture: The Triumph and the Shame and Farming in the Clouds. Subsidy-driven deep drainage for farming intensification in the Somerset Levels was also a cause celebre in the 1980s - and why the Environmentally Sensitive Areas Scheme was introduced here (following Andrew Lee's and other's campaigns about wetland destruction in the Halvergate Marshes and other areas). It is a tragedy that the ESA scheme is no more and a big concern that farmers could now drop out of the agri-environment programme, with the risk that land could be, once more, cultivated and intensified here.

It is urgent that questions should be asked about what types of land use are appropriate to the Levels. Resilient pastures are floristically diverse, with many grass and herb species that can tolerate prolonged flooding, unlike re-seeded rye-grass leys or arable land. Listening to one farmer who had just re-seeded after last winter reinforces the need to look at just what is grown on the levels and how farming can become more resilient there. Another farmer was on the radio saying he had lost a winter wheat crop. So why is winter wheat being grown on land liable to flooding - it doesn't make sense unless you are willing to take a big gamble (and lose the crop)? Arable land on the Levels also offers a potential and much greater source of silt, than does permanent pasture, that will end up in the rivers (and thus increase the frequency for river-dredging). All these considerations must be part of the big debate about future management of the Levels. Finally, any funding from the public sector must be strongly justified. We keep being reminded we are in an age of austerity and Somerset is facing a situation where cuts in public services are deep and damaging. As a taxpayer I want to see my taxes used to protect people and property where this makes sense, but not to justify the continuation of inappropriate land use practices that are going to make matters worse. 

You can see some of my other contributions to the debate here and here.