The LoftWe want to keep the central loft space for storage. Mineral wool does not perform well when crushed as it is the air that is trapped that acts as the insulation.  One option would be to put in extra cross joists to allow a layer of mineral wool between the original joists and then between the extra joists.

Another method which I have chosen as a cheaper alternative is to put 100mm of expanded polystyrene between the joists and another 100mm above the joists.  These have then been boarded out with the old skirting boards.  This will being the U value to 0.16 Wm-2K.

The skirting boards provide a hard surface for storage and spread any load across the polystyrene to stop it being damaged.

The rest of the loft will be insulated with mineral wool between and over the joists to around 300mm.

As you can see in the photo on the right the wall insulation is being continued through the roof space and into the mineral wool layer in order to form a continuous insulation envelope layer.

Between The Floors
One of the key area to address when installing internal wall insulation on an older property is the floor joists where they penetrate the wall. It is important to minimise the amount of moisture that could condense on the timbers, to remove any moisture that does condense and also to protect the timbers.

We are insulating the walls all the way from the top to the bottom of the house including through the floors.  We have therefore using a well considered approach that Parity would normally use with our clients projects which involves using lime mortar to wick any condensed water from the timbers.

Wall Insulation
We've also started putting up some of the internal wall insulation. For most of the main building this will comprise 100mm of PIR. Some 50mm and some 25mm will also be used for thermal bridging purposes.

The picture on the right is from the ground floor up.  The ground floor is 1 and a half bricks thick (~330mm) and the upper floors are 1 brick thick (~220mm).  At the junction we are overlapping the insulation i.e. for a the space between the ground and first floors it is 200mm of PIR.

On the wall with the chimney there were some joists very close to the wall.  These are only holding up the ends of the floorboards.  To allow for the insulation to be continued all the way down these are being moved in 100mm and rehung on joist hangers.

Other developments:
Installing some heavy duty straps between the main alleyway wall and the joists between the first, second and loft, and also along the roof rafters and the wall. This is being done because there has been some historic bowing of the wall and although it is not expected to move further, just to be on the safe side and for piece of mind, whilst the walls have been stripped back its an ideal time to carry out this work.

We also carried out some crack stitching to the top walls internally.

We've started lifting the ground floor floorboards to allow for the following works:

• installation of mineral wool insulation between the joists
  
• removal of a couple of bricks in the sleeper walls to allow good ventilation under the joists once the insulation in installed
  
• running a new gas pipe to a relocated gas meter at the front of the house.
  

Coming up soon - continued insulation installation, PV install, gas meter connection, new boiler and solar thermal panels, starting the electrics again from scratch and the first windows should arrive fairly soon.  Also the planning permission is progressing.......its all go.

Here are some progress photos from the top of the house moving down...

The main loft - lath and plater stripped down.  Laths have been separated and some will be used to support mineral wool under the ground suspended floor and some might be used for kindling if we put in a wood burning stove.

In the loft was some patchy and damaged mineral wool that will be reused either insulation or sound insulation in party walls.

This roof can fit around 2.25kWp of solar PV facing pretty much south.

The rooms below have been stripped back to the walls. The party wall was lath and plaster and in poor condition so couldn't be saved.

The top floor of the rear return dates from 1994 surprisingly.  This means that the roof is not too good and not too bad insulation wise.  Some damp patches required investigating so the ceiling has come down.  It turns out the damp was surface damp and so the actual roof needs no outside work.  Internally there is some PIR insulation but enough room to easily add at least 100mm more.

The roof is also easily sturdy enough to take some solar thermal panels.

Moving down the stairs.  We've stripped back to the underside of the stairs. A small amount of old woodworm on a couple of the joists will be treated and probably supported by a few additional timbers.

We've probably taken out around 4,000 lath nails by now.

The first floor party wall appeared to be a solid supporting wall but after removing the thick plaster it appears that the support is in the timber and the bricks are essentially infill.

I've just started on the ground floor and have taken the front and flank walls back to the brick. The old Victorian plaster comes off quite easily.  The problems have been where its been replaced with.....concrete!

Its worth going back to the brick for two reason i) a bit more space is saved which becomes important with the plan of to up 100mm of internal insulation and ii) the mechanical fixtures that hold the insulation in place don't have to go that extra inch to find solid brick.

And this is generally what I've been looking like for the last few weekends! Despite the effect of the dust my hair is not actually grey yet by the way - or at least not all over.

This bank holiday weekend's jobs include finishing off taking plaster down. Treating any problem wood, preserving the ends of the wood that touch the external walls and replacing nearby mortar with lime mortar (more on this later), adding noggings for new ceiling plasterboard, loosening floorboards......

In the process of taking the brick walls back to brick, the lath and plaster walls back to studs and the lath and plaster ceiling back to joists a few things were confirmed that are worth sharing...

1. It's a dirty job but someone has to do it. The roof laths and plaster contains the fine black dust of age old soot, and it gets deep into your pores.
2. Lath and plaster is heavy
3. We now have enough laths to keep us in kindling for the best part of the next ten years
4. The inner face of brickwork is rough compared to the outside and the degree to which it is rugged will determine which solid wall insulation system would work best.

5. The main point of this post is about the windows

Although not to my taste and not in keeping with the period of the property the double glazed PVC windows ostensibly looked in good condition. The seals are all intact, none of them are blown and they are all tight.

And then the window architrave came off with the plaster walls and huge gaps were discovered between the frame and the brickwork!

All the good work of the tight seals had essentially been rendered useless by poor workmanship during installation.

it just highlights the point that a building is only going to be as good as the detail that goes into it.

In the picture on the left, the light you can see just below the wooden lintel is daylight steaming in. What you can't see is the hot air pouring out or cold air pouring in during the depths of winter.

A little thought experiment....
1 - put aside any subsidies for the time being
2 - put aside any differences between the amount you pay for energy and the amount a manufacturer pays for energy
3 - put aside different carbon intensities of energy saved and energy of manufacture/tranpsort
4 - the following diagram therefore must be true when the product has paid itself off:

Therefore in a simple situation (without subsidies and with no difference in energy prices) when a product has paid for itself in energy savings it has also necessarily paid for itself in embodied energy. 

So the only question is how much to 1, 2 and 3 change things? My view is not very much. What are your thoughts - anything major missing here?  I'd love to have your thoughts.

Because of this for my project, I have decided to concentrate on paybacks and CO2 savings rather than embodied carbon as it will come out in the wash so to speak...

So we have completed our purchase and carried out some initial investigations of the property to try and convert some known unknowns - I was most worried about the floors.

The first interesting thing we found was that each lino/carpet was layed over newspapers from the date they were laid - the oldest in the sitting room being 6 months before the outbreak of WWII! Other rooms were decorated in 1950, the late 1970s, late 1980s and late 1990s.

Below are some as-is plans. Our initial thoughts are to change the bathroom to a study with a shower/toilet at the back and the Ex-kitchen into the main family bathroom.  We'd also like to build an infill extension out the back and potentially a side extension.  The former is for ergonomic reasons only - the kitchen is the heart of our home and at present is too small.  The side extension would be for numerous reasons - security being one - but mainly for reducing heat loss through the long exposed wall.  This wall would be hard to insulate internally due to the staircase running up against it and externally as the gap between the wall and the adjacent property is already tight and externally insulating would make it too small.

The floors
We pulled the corners of all the lino and carpets up in each room and lifted a number of floorboards.  Both the floorboards and the joists seem to be in good nick - a big relief.

The ex-kitchen floor is actually concrete screed on wooden floorboards. The top floor of the rear return was rebuild in 1994.  We haven't decided what to do with this yet and will depend to some extent on the junction of the floor with the walls (which we think are thermo block.)

The ceilings
My initial worries about the expanded polystyrene ceiling tiles in the sitting room and snug were also unfounded.  All see to come off easily with good plasterboard behind.  

The first floor bedrooms have a textured finish that may just need a new plaster skim.

The top floor ceilings have deteriorated due to leaks in the roof (job 1!) and so may need to come down and replaced with new plasterboard.

The kitchen roof has some old wooden slats that we will replace.  The current bathroom has textured plasterboard that is semi-deteriorated and may be replaced as lots of work will be carried out there anyway.  Finally the ex-kitchen roof, which we thought might be leaking may just be suffering from a bit of internal condensation mould in the corners instead.  We may therefore hold off replacing the rear flat roof - options remain to externally or internally insulate.

The walls
Generally good.  A few places seem to have blown plaster but otherwise good.  One wall is bowing a bit but it appears to be historic - the old paintwork on the banister is not cracked so indicates that it hasn't moved recently.  Whether we tie the walls or not will depend on what happens with the side extension.

Initial thoughts for the walls are a mixture of internal and external insulation - hopefully bringing them up to around 0.2 W/m2K.

The windows and doors
Aside from the front sash windows they are all good quality double glazing. The ex-kitchen windows being a bit older.  An work to these will be purely aesthetic as the energy improvements will be negligible.

The front sash windows we hope to restore and DIY secondary glaze - the expense of new double glazing or even triple glazing would not lead to any substantial savings and would cost a bomb.  The windows actually have old sliding shutters beneath which we may restore.  This would mean we might insulate the wall beneath the windows externally - watch out for details on avoiding thermal bridging.

The doors will have to wait on what we end up doing with extensions.

Heating and hot water
The less said the better! Gas room heaters, night storage heaters, 60% efficient gas domestic hot water boiler and an electric over sink instantaneous hot water heater.  These will all be going to be replaced by.....
...probably a top specification gas boiler, maybe a combi maybe not, maybe solar thermal on the ex-kitchen flat roof.

We've exchange!

It took a long time and a fair amount of ups and downs but we got there.  Now the planning starts in earnest.

And here is a picture of the house...

The house has three separate roof areas, and luckily for this blog, three roof types. The main roof is has around 50mm mineral insulation between joists. The front of the house has a bay with its own small roof which has been modelled with no additional insulation installed.  The rear extension has a flat roof that was replaced in the mid 90s.

I've used our masterplan software to model the changes - I've set the base model to have a top efficiency boiler rather than the antiquated heating systems that are currently in place as I will definitely be changing this.

Bay Roof
The bay roof has been modelled with around a U value of 2.  There also is not much space to add additional insulation.  What are the options?  The void can be filled with insulation - some mineral wool or potentially something with a greater insulation value for smaller depth such as XPS or even more such as PIR or phenolic foam board.  This could be added from the outside but would require the tiles to be removed, or internally but would require the ceiling to be removed.  Another option is to insulate the inside face of the ceiling of the bay window.


Since I will be taking some polystyrene ceiling tiles off the ceiling of the room, and also I want to look at the timbers of the floor above I will be taking the internal ceiling of the bay down. I'll then insulate with foam board and then apply new plasterboard.

Estimated cost: £50 (DIY measure)
Saving: £3.30
Payback: 14.79 years

Flat Roof
The rear roof is a flat roof built in the mid 1990s and probably has a U value of around 0.35.  A new Building Regulations roof would need to have a U value of 0.18 or better.

If the roof was in good condition it could be insulated on the inside to keen the costs down.  In this case the roof requires some work to weatherproof it.  Strictly speaking this means it will need to be brought up to Building Regulations anyway. Scaffolding will probably be required to carry out weatherproofing works so I will be looking into quotes to bring it up to current Building Regulations as well as getting a solar thermal system installed on it at the same time.

Estimated cost: £1,000 (Professionally done)
Saving: £3.56
Payback: 281 years

Main Loft
The main loft is a standard pitched roof with around 50mm of insulation installed between the joists. This insulation is in a pretty badly installed.  Cheapest and easiest solution is to top up the insulation between and over the joists to 300mm.

Estimated cost: £250 (DIY measure)
Saving: £45.48
Payback: 5.5 years


Another option being considered to have a central area that has 100mm mineral wool between the joists and XPS board insulation and chipboard above the joists so that a solid platform remains for storage.  this will cost a little more but should result in similar savings.

Whist I've got the loft ladder out I'll be carrying out some work on the loft hatch:

Loft Hatch Insulation
Estimated cost: £10 (DIY measure)
Saving: £2.32
Payback: 4.3 years

Loft Hatch Draughtproofing
Estimated cost: £7.50 (DIY measure)
Saving: £2.09
Payback: 3.6 years

The house has a range of different types of window ranging from bay windows at the front, a single glazed top light above the front door, to 15 year old uPVC windows in most of the rest of the property.

For this exercise I've ignored three windows - the dining room window and side kitchen window as they will be altered as part of a potential extension, and the tiny toilet window as I haven't decided what to do with it yet.

When we model changes to windows as part of our Masterplan, changes to solar gains are included in the calculations as we take into account the amount of light that comes through different window types as well as their orientation and the geographical location of the house.

I've presented the results in a different format to highlight other useful ways of looking at savings other than just absolute financial or CO2 savings.

The peach rectangles represent the £ expenditure per annual £ saved by the measure - i.e. the smaller the better and also they are essentially equivalent to paybacks - £25/£ saved ~ 25 year payback.

The orange cylinders show the £ spend for each annual kg CO2 saved.  Again the smaller the better.  ~~Both of these represent cost effectiveness of measures either in saving money or reducing CO2 and are useful for setting thresholds. In the graphs I have set a £25/£ saved threshold as indicated by the red vertical line - only measures that don't exceed the line will be considered from an eco perspective.

It's Christmas so I thought I'd spoil myself and do some additional fun analysis on Air Source Heat Pumps and different Coefficients of Performance.  (N.B. as with other analysis this is only valid for the house I am looking to buy.) For those that don't know a Coefficient of Performance (COP) is the % heat energy that you get out of a heat pump compared to energy in.  An example is a COP of 200 means you get 200% energy out for energy in or twice as much energy out as energy in.  I know it sounds like some basic laws of physics are being broken but they aren't.  The energy in is actually 'work' and the energy out is the conversion of low grade heat (in the outside air) to high grade heat (inside).  The COP therefore doesn't take into account the amount of energy in the low grade heat as it is essentially free.

The graph above shows the results of my efforts.  The yellow line is the basic savings that can be expected compared to the current heating system in the house.  You can see that a COP of 225 is required for there to be benefit.  The blue line is the savings including a rough figure for the Renewable Heat Incentive payments - in this case a COP of around 120 is required.  For these calculations I've using a one tariff electricity rate. Anyone want to share their thoughts?

So the results of the initial heating system analysis are in...for this analysis I haven't carried out any behavioural or zoning analysis or changes to the shower heads.  The model therefore has the whole house heated to 21 degrees - 2 heating times during the week and one longer one on weekend days.  For each system I have modelled putting in modern controls appropriate for the system i.e. thermostats, radiator valves, boiler interlock

To begin with I looked at 9 different major changes to the current heating system (electric storage heaters supplemented by gas room heaters on the ground floor):

1. A top specification condensing combination boiler for a radiator heating system and hot water
2. As 1. but with the addition of a weather compensator
3. A top specification condensing boiler with a modern fully lagged 200litre cylinder and lagged pipework for a radiator heating system
4. As 3. but with the addition of a weather compensator
5. As 4. but underfloor heating
6. An air source heat pump system for the heating and hot water (coefficient of performance used - 2.5)
7. As 6. above but using the average coefficent of performance found during recent Energy Saving Trust fieldtrials - 1.94)
8. As 7. above but with the heat pump for heating only.  The hot water being provided by an electric immersion heater.
9. As 7. above but with an estimate of the Renewable Heat Incentive payments based on original consultation figures.

So what does all this mean for our heating system decisions? Personally I'd like to see a bit more independent data on the performance of air source heat pumps in many different scenarios.  Even without this the paybacks don't seem to be as good as for the gas boilers. I'd also like to see more information about the long term performance and life expectancies of air source heat pumps.  Finally I'm not sure I'd be comfortable with such large payments which would essentially come from people who either did not have the means to install an air source heat pump or other RHI plant.

All this means is that although no decisions are being finalised at present, I'd going to model the property with a gas boiler. As it is a fairly large house and will have two bathrooms I'll also model it with a hot water cylinder. I'm going to have as the base case a radiator system but will evaluate underfloor as an option.

There are other considerations that will come into play with regards to the radiator vs underfloor decisions such as the floors being taken up for rewiring, plumbing, insulation (and potentially damp remediation).  Finally as the walls will probably be insulated over a period of time, it will be best if the central heating system was installed throughout first and did not need moving over time - radiators would unless I was to have them standing over 120mm away from the walls to start with.