Neighbours Wookey and Rob Leedham explain why they were motivated to retrofit their homes, how they built up knowledge and why engaging with others on a similar path has been extremely useful.
Interview with Wookey and Rob Leedham
Neighbours Wookey and Rob Leedham share their experiences on their individual retrofit journeys. With technical minds and a passion for problem solving, this pair of DIY retrofitters have undertaken a vast range of tasks, from installing external wall insulation (EWI) to building a ground source heat pump! In the process they have saved a lot of money but we look at why they were well suited to this DIY approach and the value that they have taken from networking with fellow retrofitters (through green building organisations such as the AECB).
Wookey’s retrofit
Wookey’s journey began when he and his wife bought a house in Cambridge that initially looked presentable and tidy. However, it was draughty and not particularly comfortable and soon they decided to retrofit it. Having hired builders in the past and not been completely satisfied with the standard of work, Wookey decided to undergo the renovations himself.
The existing dwelling is a 7 x 8 metre square, 1960s detached house with a separate garage. During their renovations they began by insulating the loft and replacing the front door. They then continued on to wall insulation, both internal and external in different parts of the house. This was followed by replacing the old and inefficient boiler, which is now also about to be upgraded to an air source heat pump and eventually replacing all of the windows. Furthermore, Wookey chose to build an extension that connected the house with the garage and added a sun room.
As the existing house is masonry cavity wall construction Wookey decided to keep things simple and construct the extension in the same way. They did hire a builder to put up the superstructure but Wookey undertook all the internal work, fitted the underfloor heating, tested the airtightness and even learnt how to fit an air source heat pump.
This DIY approach has been time consuming, with it coming up to a decade of renovations. However, it has also allowed them to save a remarkable amount of money.
“I learned quite a lot from having done it mediocrely once [renovating his previous property] and going, right, this time we’re doing things properly.”
DIY allows you to control the quality of the work
DIY projects can be stigmatised as below a professional standard, but Wookey explains that DIY has enabled him to get a much better finished product. After some bad experiences with builders cutting corners, Wookey found that doing the job himself allowed him to get the standard he wanted and all the details correct.
In Wookey’s experience, the nature of the building industry means that the right way is considered to be the one that gets the job done in the fastest time.
“The real problem with tradespeople is that everything’s time based. How many hours is this going to take? So they won’t necessarily thread the plumbing or the wiring in the right place, they’ll do whatever they can get at in half an hour, rather than doing it properly which is literally going to take 10 times as long. I think that’s the main advantage of doing things yourself is you get those little details right.”
Having a long-term plan for your retrofit is essential
It is commonly recognised that an over-arching retrofit plan is very important to ensure a successful project, mainly because it will help to avoid having to retrace steps or undo your work. DIY retrofits can take a long time and if you choose to live at home during that time, it will likely happen bit by bit or one room at a time. For example, replacing your windows without considering how it links up with insulation may be a missed opportunity.
Modelling your home in PHPP is invaluable
Wookey also decided to do the energy modelling for his home himself. Initially he was reluctant to use PHPP but discovered that it was fairly straightforward and offered a lot of benefits. It is a great tool for retrofitters as it helps you plan your retrofit, predict the potential performance of your house and identify what is needed in order to reach a given outcome. Sarah Lewis from the Passivhaus Trust helped us break down the topic of PHPP, providing an in-depth explanation of the benefits and sharing her own experience on a retrofit journey.
“I put PHPP off for a long time, because it’s a pain in the arse and it took a month from a standing start, even though I kind of understand the principles. But you know, it’s just if you’ve not done it before, it’s hard. But then you realise, actually, we could get to EnerPHit or at least pretty close on this house.”
You will need a certain set of skills for a DIY retrofit
Wookey’s background is in software engineering and he has always been interested in fixing his own cars. This meant that shifting his mindset to building physics wasn’t too difficult. Wookey advises to anyone starting out on this journey to spend the time learning the processes and discovering the how and why. Wookey admits that it can be a bit difficult to find this information online, but the Denby Dale Passivhaus study is a great place to start as they provide clear examples of where techniques have worked. This is also why retrofit and self build communities such as Cambridge Carbon Footprint, Cosy Homes Oxfordshire and The Hub here at House Planning Help are amazing resources that allow you to ask questions and learn from experts or others who have already been through the process.
“I’ve got a fair amount of practical skill. I’ve always fixed my own cars and that was where it started… and electronics. Buildings are quite simple in comparison to cars and electronics! It’s often fairly basic stuff. It’s mostly a matter of understanding building physics.”
There is a shortage of green builders in the UK
Wookey explained that in the Cambridge area and many other parts of the UK there is a real shortage of tradespeople who are experienced in sustainable construction. Hopefully this will change over time as demand grows and the industry comes to understand the need for attention to detail. In the meantime this might be another reason why a DIY approach is preferable.
Some areas are worth paying the professionals
Tiling and plastering were two areas where Wookey decided to bring in a professional because they both require a level of practiced skill in order to achieve a good quality outcome.
Wookey also paid £1500 for some drawings for his extension, but did end up regretting this as they designed a standard box that didn’t consider energy efficient principles. As a result, Wookey ended up drawing his own plans and only used the plot measurements from the initial drawings to aid his own design. This offered him the freedom to create exactly what he wanted, however there is an added pressure to this and if things are calculated wrong then that is your responsibility.
“Generally, my assumption is that I can do everything, and it turns out that’s true for everything… apart from plastering, that’s the hardest thing in the world.”
DIY retrofits can be all consuming, it is important to maintain a balance
A DIY retrofit can be a long and time consuming process. For Wookey, the challenges and puzzles are enjoyable, but they can become all consuming if you are not careful. Wookey and his wife decided early on that at least one weekend a month they would do something other than DIY to ensure that they maintained a good balance. Wookey also highlighted that it was easier to give so much attention to their retrofit as they don’t have children and the commitments that come with family life.
Guy Hargreaves employed a contractor to carry out his retrofit. Watch our in-depth video case study in The Hub.
Many people are interested in retrofit but not the DIY approach
Since undergoing his own retrofit Wookey has encouraged family, friends and colleagues to consider taking on their own projects. While they understand the potential benefits a retrofit can deliver they do not always warm to the DIY approach! So, you can of course bring in a contractor to do the work.
DIY retrofits are a great option for people who have a passion for doing the manual work, enjoy learning and have plenty of time available.
“A surprisingly large fraction of the people I meet, think, yes, that is a good idea and I should definitely find out about it, a very small fraction of them want to do it as DIY or take ownership, they don’t really want to learn about the whole thing. They just want somebody to do it and there’s a terrible shortage. There aren’t enough people around here at the moment. I know several people who’ve been quite keen, and have tried to get quotes and struggled or been told that we can come and get to you in two and a half years time.”
You will begin to notice the benefits
Wookey explained that as well as the obvious benefits of an energy-efficient house being cost effective and warmer, they also began to notice small things that improve their daily life. For example, when you achieve a good level of airtightness and have triple glazed windows it becomes more peaceful. Also dust mites disappear when the MVHR is running and keeping the home within an optimum humidity range.
“When you go and rent somewhere to stay, you go to these cold and draughty rented cottages. And you think it’s not like my nice house at home. So you get quite picky about buildings once you’ve tried living in one that’s actually good.”
Rob Leedham’s retrofit
Wookey’s neighbour Rob Leedham has also been gradually improving his home. Rob and his family have lived at this house for 23 years and although he had no grand plan at the beginning, he has been consistently adding one green measure after another.
Rob has undertaken the whole of his retrofit as a DIY journey, including installing 150mm of External Wall Insulation (EWI) on all external walls and insulating the footings of the house. Rob is also passionate about solar power and energy generation. 12 years ago they installed solar PV panels on the roof and have more recently hooked it up to an inverter that will be able to accommodate both additional solar panels and batteries for energy storage.
Community access to airtightness testing kits will help make the retrofitting process more affordable and more accessible
One of the trickiest parts of retrofit is reducing the air leakage of a property, which calls for a good airtightness strategy. Having the airtightness layers all in place is not enough – the airtightness needs to be checked and then further leaks can be identified and addressed.
Rob showed Ben two fans that can be used for testing. One is a professional blower door kit and the other is a homemade version. These can loaned to other retrofitters in the area. A standard airtightness test is time limited and will cost around £300. Rob’s hope is to get a few for their group in Cambridge so that retrofitters can take their time to achieve the best airtightness results possible and not feel like they need to rush on.
Using their airtightness kit, here are the current findings for both Rob and Wookey:
- Wookey had aimed for below 1 air change per hour (at 50 Pa) and is currently measuring at 1.52.
- Rob had aimed to get his below 3 air changes per hour and is currently measuring a 2.1.
Rob’s DIY blower door kit!
Rob built his own ground source heat pump
Rob is also technically minded and opted to build his own ground source heat pump from scratch.
“The thing about ground source heat pumps is that they are actually very simple. There’s a compressor or an expander, and a pump and two heat exchangers. That’s basically it. So it’s not that hard to build your own. Some parts of it are inside and some parts outside. And so the electronics is inside and the header tank. And there’s a little display there that says it’s got a coefficient of performance of 4.4 at the moment. So inside, we’ve got that part that calculates the efficiency. And there’s a little electric meter, a standard electric meter for measuring how much electricity is used. It’s been going for about two years and a couple of months, and it’s up to four megawatt hours of electricity in to provide all of the heating and hot water for those two and a bit years.”
The key to heat pumps working efficiently is a well insulated house that doesn’t need much heat.
Rob does not recommend this route however unless you really enjoy the process and recognises that the sensible choice is to buy one and have it installed by a professional!
Stuart Dyer’s retrofit
Stuart Dyer is another member of the Cambridge retrofit community and has been retrofitting a 1930’s detached property. Stuart took a different approach and moved out for a year whilst they carried out an extensive retrofit. The process included external wall insulation, triple glazing, fitting mechanical ventilation with heat recovery (MVHR) and installing an air source heat pump. Stuart highlights that one of their biggest challenges was get their airtightness to a good standard and they worked quite hard on this area. They also put in underfloor heating, which works well with the air source heat pump, and insulated quite a lot under the floors.
Stuart likes being in Cambridge because there is quite an active retrofit scene, consisting of monthly meet-ups of the Association for Environment Conscious Building (AECB) (that Wookey organises). This offers a great chance to meet with people in the pub, discuss with those who have already done a lot of work, the good things to do and the pitfalls to avoid. Transition Energy Group is also quite active in terms of new technologies, new interests, and there is a lot of good advice there. Cambridge Carbon Footprint have lots of great case studies and also runs an Open Eco Homes each year where you can visit other people’s houses, whether they are new build Passivhaus or up to EnerPHit standard.
Search for ‘green building’ meet-ups in your area
In every town or city there will be opportunities to network with like-minded individuals and professionals by tapping into local green building groups. These are often as much about inspiration as sharing knowledge but it’s particularly useful for those on a DIY journey who may encounter challenges and be looking for advice or contacts.
Find out more
Association for Environment Conscious Building (AECB)
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