The South facing gable end of the barn has been one of the biggest issues we’ve faced. It always looked very sound and had been repointed recently. Once work started it become apparent that the pointing wasn’t as sound as it looked – in fact the higher up the wall you went the worse it looked. I even managed to find stalactites-in-our-walls – which was nice. The wall is pretty exposed to the valley and gets all that wonderful rain thrown at it – a lot of which seeps in through the dodgy pointing just doesn’t want to leave until it seeps out days, weeks even years later.

The prospect of repointing the wall and finding the problem persist wasn’t one I savoured so another solution was required. White washing was something I’d considered and read up on – as an aside, for anyone interested in this area or facing similar problems, I’d recommended Precious Inheritance: The Conservation of Welsh Vernacular Buildings by Cliff Blundell – as it says in the title the focus is on Welsh vernacular buildings, but is relevant to most British pre World War One buildings. There is a case study of a coach house in Carmarthenshire with a damp ‘pine end’ (sounds uncomfortable!) that gave me the confidence to consider applying a similar solution.

So when the builder suggested bag pointing the wall (as we’d done inside to tidy up the internal wall) and then lime washing I was all for it. Having seen it done elsewhere we went ahead.

I just hope it works!

Whilst bringing to mind images of ticks and leeches, parasitic architecture is an umbrella term, used to refer to self-contained new buildings that are attached to an existing structure. Parasitic because of the use made of existing infrastructure.

Personally, after the time and energy that have gone into my barn conversion project the prospect of picking a unit and dropping it on site is very attractive. A few examples…

spacebox >> spacebox.co.uk
Closely resembling storage containers of the type used to transport goods by sea and road, spacebox is a Dutch designed:

‘…high specification low-cost, studio-housing unit that can be installed and moved quickly. Site preparation is faster than traditional multi-occupant buildings. Each studio contains a fully specified kitchen, shower-room cum WC. Water, electricity, sewerage and telephone connections are fully integrated at the manufacturing stage.’

These rectangular blocks can be painted a custom colour to blend with their surroundings and can be quickly commissioned on site as they come preprovisioned with all the usual amenities and merely need coupling up to services. They are aimed a the ‘low’ end of the market – student / temporary accommodation.

Lift-Up House >> turnercastle.co.uk
Another example is the Lift-up House ia two-bedroom apartment seemingly flown onto the roof of an industrial building in Hoxton, London.

Las Palmas Parasite >> kortekniestuhlmacher.nl
A striking protuberance on the lift shaft of a building in Rotterdam.

The Las Palmas Parasite was a prototypical house aiming at combining the advantages of prefabricated technology and the unique qualities of tailor-made design. The limitations imposed by the size of the elevator shaft demanded a compact plan and volume.
The object was supported by the walls of the existing building. Services like water supply, sewage and the electric installation had been linked to the existing installations.

loftcube / Werner Aisslinger >> aisslinger.de
Werner Aisslinger is a German furniture designer who also designed the loftcube, a ‘modular living unit’ that can be tailored internally and externally to the desires and needs of the residents. The module can then be lifted into place.

As Autumn (and an end to lime pointing) approaches things have come on at the barn.

Plastered!

We’ve been plastered. Plastering has been completed except for right at the ‘top’ of the barn, where the ceilings have yet to be completed. Cabling and pipes for the solar panels and other services are carried through a small roof space that we can’t close up until everything is in place. The plastered walls give the whole place big push away from being a barn to being a house.

I managed to get the top of the west facing aspect of the barn repointed before we went to France for a couple of weeks – if Winter holds off for long enough perhaps I’ll get the bottom completed!

Internally the one wall we can leave uninsulated has been bag pointed on the living room side and in the kitchen (you can see it to either side of the opening in the picture above) – the finish pretty much covers the stones, but it should be a cleaner, less dusty alternative to repointing and the wall was in pretty bad shape in places. The remaining bit (in the main bedroom) I think we’ll leave as exposed stone.

Installation of the solar panels is in progress, a slight hiccup in locating them on my awkward east-west facing roof has meant I’ve had to go back to planning – I’ll write more on this once the whole saga run its course.

There may be a glimpse of an end being in sight…October (hopefully) holds plenty more progress…

Many people visiting this site are looking for information about heat pumps, being one who believes in giving the people what they want I thought an up-to-date summary was in order…

Heat pumps take heat from a donor heat transfer medium (earth / air / water) and condense it for the purpose of heating water or air.

The basis of heat pump technology is something we are all familiar with as it is similar to that used in refrigerators or air conditioning units ~ but in reverse. The heated water generated by a heat pump is often used for space heating but can also be used as the basis for general hot water provision given an additional boost from a complementary boiler system to raise water temperature.

Heat pumps consume electricity to power the compressor & pump that circulate fluid and gas around the system; this is a relatively efficient use of energy typically producing between two and four units of heat for each unit of electricity consumed. The ratio of energy consumed to heat generated is know as the coefficient of performance (COP). There is a theoretical limit of around 14:1.

What types of heat pump are there?
The air source heat pump (ASHP) draws thermal energy from the air.

The ground source heat pump (GSHP) gathers heat from a ground loop. This is constructed from lengths of pipe filled with a blend of water and antifreeze in a closed loop. This loop is buried in the earth either horizontally in trenches or vertically in a bore hole.

The water source heat pump (WSHP) uses water as the heat transfer medium.

How do they work?

• A liquid refrigerant is forced through an expansion valve & in doing so it loses pressure and evaporates.
• In evaporating, the liquid refrigerant removes heat from the input loop. The exact nature of the input loop will vary depending on the type of heat pump as discussed earlier ~ in general terms it brings heat energy to the evaporator coil from the donor medium.
• Cooled water in the input loop is recirculated and reheated by the transfer medium.
• The evaporated refrigerant passes through the compressor that increases pressure and causes the refrigerant vapour to condense at an increased temperature.
• As the refrigerant vapour condenses heat energy is released, this heat raises the temperature of the condenser coil which in turn heats water.
• This water is then used for space heating.

the basic structure of a heat pump

Where should I use a heat pump?
They are best coupled with well insulated, energy efficient buildings with an under floor heating system for heat distribution. Traditional radiators can be used, but will need to be larger in total surface area than those found as part of a conventional system due to the lower water heating temperatures, such a system will also be less efficient than an underfloor alternative. Air source heat pumps are often used in conjunction with ducted air heating systems.

You will need plenty of outdoor space for a horizontally installed GSHP ground loop. Alternatively, a vertical bore hole can be sunk but will cost more.

Bear in mind that the payback period will be longer if the heat pump is replacing gas rather than other heating options such as solid fuel or electricity. However, with soaring gas prices the payback period is shortening.

The higher the temperature that water is heated to, the lower the COP of the pump will be. Bear this in mind in designing your overall hot water system, providing additional inputs to raise water temperatures to domestic hot water (washing) levels.

How much do they cost?
Costs have remained relatively static over the last year, a 6kW ASHP costs around £3,500 with a larger 12kW pump coming in at about £6,000. You will them need to pay for installation and excavation, this will potentially double costs, so allow £6,000 to £12,000 for a domestic installation. This excludes the cost of the distribution system such as an under floor heating.

Summary
Future developments, such as photovoltaic cells with a shorter payback time or more exotic combinations for example, bio-fuel driven Micro Combined Heat and Power (micro-CHP) installations providing input electricity, offer greater levels of sustainability and self-sufficiency in heat pump utilisation. This doesn’t stop heat pumps from offering a green heating solution today, with guaranteed CO2 savings over traditional heating systems and a relatively fast payback where mains gas is not available.

Other Resources
Grants may be available for UK installations see http://www.lowcarbonbuildings.org.uk/micro/
Proceed with caution where gas is available according to carbonlimited.org

Previous Heat Pump Articles on MBC
GSHP
ASHP

I’ve given my opinion and explained the pragmatic approach to project management (some might call it a lack of management) that I employ. I’ve also described some of the tools that I use … Google documents & Basecamp … and some of the questions to answer when deciding ‘how to manage your project‘.

Progressing with this I’d like to suggest to any would-be renovator to not over-manage or over-control your project. A successful renovation project requires skilled and talented people to be engaged and translate their talents into tangible parts of your renovation. With all the will in the world, there will be elements to your plan or your plan that are not optimal and that these individuals are better equipped and are better able to decide upon or specify. So let them do so … listen, take advice, get an feel for costs and time-scales, then make a decision.

Don’t try to make all your decisions up-front and don’t try to be the sole decision maker. There’s no way that on your own you’re going to get it all correct all the time, but with help and advice you’ll get more correct, more of the time.

From a management and control perspective this means that you’re going to need to leave some decisions until later, to allow aspects of your plan to evolve over-time. Start off with a plan by all means, just don’t expect it to be followed exhaustively, or feel bad when reality diverges away from it.

Follow the path to your goal and expect to make a few diversions along the way.

…and don’t forget to buy a good notebook…