Category Archives: sustainability

‘Spectacular’ green roof in Dulwich

I built this one last week on a garden office in Dulwich. I don’t do so many sedum roofs but this did come up looking really nice and is instantly green.

The roof build up was using the Optigreen lightweight roof system. A protection fleece over the waterproofing, drainage layer, lightweight substrate and pregrown sedum on top. This was ideal for this garden office and really helped it blend in to the trees and plants at the bottom of the garden. The roof will drain into a gutter when complete (not that there will be a lot of runoff). I used aluminium edge trim all the way round to give it a nice defined edge.

The substrate was incredibly dry when it arrived, I initially thought it was just sand! This made it really easy to get up on to the roof, the bags weighed even less than usual. Luckily it has had a good soaking with the rain since to get it nice and wet.

Getting the sedum up on the roof was a little trickier, we left it out overnight and the client enthuisiastically watered it making it very heavy. After struggling with a couple of rolls I realised it was better to cut the mats in half to make them easier to handle.

Once it was all up it looked really good. I spoke to the client again the week after to check on it and he said ‘It looks absolutely stunning. The wife and my nearest neighbours really like it – so a big thankyou. I have been diligently watering it and it is looking good. Many thanks‘ very pleased with the feedback.

Green roof on a bike shed

This is a project I completed back in October, secure cycle storage and a green roof. The client wanted secure storage in the front garden without having a big ugly box taking up all the space for planting and we came up with this elegant solution.

Still flowering in March

As the shed is on the way into the house we planted a number of different herbs which can be easily picked when you are on the way home and also release a scent if you brush past. These were combined with some flowering plants (it was October so not much available) and sedums. The whole roof was also sown with wildflower seeds so should be quite productive in the spring. There are saffron crocus bulbs underneath which may start to appear in late summer.

Freshly planted

The bike shed itself has capacity for 2 bikes but there is a larger 4 bike version or these can be put side by side for multiples. To order.

This type of roof can be more easily accessed by the householder so we can try and create a slightly more formal garden than I would on a normal green roof as you can change the plants around and water and feed them if it is necessary.

The green roof itself has a fleece at the bottom then a drainage layer of aerated clay pebbles before the soil, here to about 125mm depth but the sheds are pretty tough so this could be bigger if required. The sleepers look really good but an alternative would be cobbles in gabion cages depending on what would fit with your front garden. Order page.

My Shabbihaus eco retrofit project part 2 Boiler replacement

This came about through problems with the old boiler rather than careful planning. Firstly I replaced the thermostat with a Smart controller, this was about 5 years ago and the choice was limited but I got an Owl controller which allowed us to control the heating with a smart phone.

This allowed us to monitor electricity use as well as program the boiler simply online and turn it off for holidays etc. The controller was easy to fit as you replace the existing thermostat and use the same wiring. Once this was done the heating started coming on only when the temperature in the house fell below the required temperature we set. The previous controller turned on the heating when it was programmed to, regardless of the internal temperature and waited for the thermostat to turn it off again. This fine control and ease of use saved us 10% on our gas bills straight away.

The monitor really helped us concentrate on electricity use around the house and focus on reductions, however it also coincided with having kids and being at home a lot more so our usage actually went up for each successive year, as shown below. Now they are a bit bigger we are out more and using the meter to concentrate their minds too and starting to take our usage down again:

The boiler was an old Worcester and only about 64% efficient. A fault developed with it so it started heating up radiators whenever we used the hot water so we decided to get rid of it. I did plenty of research and luckily enough this coincided with Ecobuild so I was able to go round stalls there to look at a good range of boilers and ask silly questions. Efficiency of most boilers is well over 90% so my main concerns were how it would fit in my kitchen and reliability. I eventually settled on an Intergas boiler, not quite so common in the UK but it came with a 10 year guarantee and has very few moving parts and good reliability.


Very pleased with the boiler and five years later there have been no problems. We are warmer, the shower works better and our gas bills went down.

Very pleased with the boiler and five years later there have been no problems. We are warmer, the shower works better and our gas bills went down.

We also got TRVs installed on all the radiators.

My Shabbihaus eco retrofit project – part 1 introduction

Many of you, like me, will have listened watched or read about a wonderful renovation project where the house has become a wonderful palace of efficiency, costs 10p a year to heat and it’s the most comfortable and relaxing place in the world. You gaze on in envy at the ventilation, triple glazed windows and wonderful insulation. Then comes the tipping point, what did it cost for this the interviewer asks? ‘Oh, only £80,000 on top of the cost of the building work’ and at that moment you realise this is never going to happen in your home.

So, what can you do without breaking the bank? I thought I would share some of my experiences of trying to improve my property on a tight budget, with a low income and the property occupied throughout.

Ideally you would start with a whole house plan for your property, this includes an assessment of the general condition of the place and a list of all the efficiency improvements that it is possible to make to the property. You don’t need to carry them all out and certainly not all at once but it gives you a path for the next 10 years or so, you can also tie this in to any other projects you are planning, redecoration, extensions etc. You can see mine here.

Of course I didn’t start with this, I started when the boiler broke but I have got round to it now and I don’t think I got too far off course. The other thing you should probably do is monitor the conditions in the house so you can get a picture of it’s performance and the effect of the changes you make. I have been even worse at this but have some stats on energy use  that the smart meter collected, otherwise it comes down to ‘we felt warmer’ and ‘the mould didn’t reappear on the walls’. Still I am quite happy and it’s slowly getting more comfortable.

So, what did I and what did it cost, here we go in chronological order with the points where it coincided with other works, details to follow over the next couple of weeks

Putney roof insulation

The first stage of this project was replacing the insulation in the sloping roof of the dormer and adding storage to the eaves. The loft conversion has been done reasonably well and the flat roof area and rear wall properly insulated. 

#putneyretrofit
Original insulation showing the gaps and missing sections

However the existing sloping roof was not so successful. Polystyrene insulation had been installed between most of the joists, but not all, not sure why but they had missed some areas leaving big gaps in the insulation envelope.

#putneyretrofit
Starting to insert insulation between the rafters. Still some gaps to fill.

We replaced the 50mm of polystyrene with 50mm of KIngspan between the joists to create an airtightness barrier we filled all the gaps with Isocynate free expanding foam and then taped

them with aluminium tape. Then we added a further 50mm of insulated plasterboard below the joists.

Many loft conversions leave the eaves storage area uninsulated and the doors can prove a weak

#putneyretrofit
100mm of rockwool going between the rafters in the eaves storage area.

point with the wind whistling through them. We had already added rockwool to the floor area and we took the wall/roof insulation down to meet this and insulated the end walls as well creating a ‘warm’ storage area.

Reclaimed materials in side return extension in Hackney

A side return infill extension with an industrial style. Extensive use of reclaimed materials, high standards of insulation and a wildflower green roof.

We completed this project late on last year working with Clements Design as the architects.

The project aimed to turn a cramped kitchen into a spacious area for cooking, eating and socialising. There is an industrial and sustainability theme to the project, the materials used are often from or designed for factories. Electrics are contained in galvanised metal conduit and the floor is concrete. Walls are exposed brick, both reclaimed glazed brick and the existing London stock bricks revealed to the world. The large glass panels to the roof draw in light to what was once a dark area and bring out the rich colours in the reclaimed wood cladding.

Though the materials could be seen as austere they are softened by the contents of the room that reflect family life, there is space for a large wooden toy stove, a comfy sofa and a gorgeous oak dining table with mismatched chairs.

The large rear doors mean the garden can be seen and accessed easily from the house, the doors can be flung open in the summer for barbecues. The green roof will develop over time but already has wildflowers peeking over the parapet and they can be seen swaying through the glass roof.

The project was also designed in conjunction with the neighbours and they share the party wall and the box gutter.

Sustainability was a key part of the client’s aim for the project. Reclaimed materials were used wherever possible. All the bricks removed in the demolition stage were cleaned and re-used onsite to build the new structure. Internally there are two walls of glazed bricks reclaimed from a lift shaft in Kensington. The other walls are the original brick exposed and insulated on the outside where appropriate. The bi-fold doors are triple glazed with a u-value of 1.09 are factory finished for long life and are made from environmentally sourced timber from sustainable forests. The heating is underfloor and utilises the existing condensing boiler, three Nest controls were added to the system to control this and create two new heating zones in the house.

The wood (for drawer fronts, shelves and cladding) is from a reclaimed wood specialist in Guiseley, Leeds, called Machells and is cut down from Yorkshire Victorian mill joists.

The large pendant lamps are reclaimed from a 1950’s factory in the Stoke area.

The table was made in Leeds from British oak 35 years ago.

All the shelf brackets and drawer handles were made in England in foundries using all traditional methods.

All lighting is LED, even filament style traditional bulbs are actually LED.

The green roof is part plug planted and part seeded with a mixture of wildflowers, meadow plants and some sedums. The roof will flower through most of the year and provide habitat for insects and foraging for birds amongst other biodiversity benefits.

Reclaimed bricks and cladding looking great

We have nearly finished the extension we have been working on for the last few months in Hackney. The walls, roof and floor are all in place and there is just fit out for the inside and the green roof to go on top.

The glass roof had to be lifted into place by hand
The glass roof had to be lifted into place by hand

The yellow London stocks were reclaimed on site. The doors have a u value of 1.09 including the frame
The yellow London stocks were reclaimed on site. The doors have a u value of 1.09 including the frame

All the wiring is in galvanised steel conduit. The exposed bricks will be protected by external wall insulation on the outside.
All the wiring is in galvanised steel conduit. The exposed bricks will be protected by external wall insulation on the outside.

The glass, reclaimed cladding, exposed steel and reclaimed bricks really work well together.
The glass, reclaimed cladding, exposed steel and reclaimed bricks really work well together.

A lightweight industrial screed is making up the floor
A lightweight industrial screed is making up the floor

Green roof in South London

Last week I completed another green roof in Streatham. It is on the rear of a really interesting house, a 1930s semi that is getting a complete eco-makeover from the owner. He has insulated the walls inside and out with wood fibre and remade the roof in solar panels and that is just the start. All Stephen’s neighbours find it hard to believe how warm the house is without loads of heating!

Anyway, last Wednesday he set aside so I could come along and help him build a green roof, here are the photos:

The roof is on top of this single storey extension
The roof is on top of this single storey extension

The first layer of the green roof, a fleece to protect the waterproofing and retain some of the water.
The first layer of the green roof, a fleece to protect the waterproofing and retain some of the water.

Then we added a drainage layer to encourage free draining.
Then we added a drainage layer to encourage free draining.

Next is the root barrier and then special substrate
Next is the root barrier and then special substrate

We planted the roof with sedums, widlflower plugs and sowed a selection of wildflower seeds
We planted the roof with sedums, widlflower plugs and sowed a selection of wildflower seeds

The finished article
The finished article

It should grow and develop over the next few years until it reaches maturity.
It should grow and develop over the next few years until it reaches maturity.