Bryn Derw Renovations and future proofing the property

What are jobs are you carrying out at your property?
We’ve purchased our 1930s build house in 1930s, and it needed a significant amount of renovation work doing, due to this house not really been touched since it being built. 
Major jobs included:
New drainage
New plumbing
New heating and hot water
Insulation
Double glazing

The list is not exhaustive by any means, but these are the big ticket items.

What previous experience have you had prior and where did you learn?
Before starting this renovation, we’ve not had major hands on or building experience other than some basic DIY. Everything we know today was learnt from research, YouTube, online courses, attending trade shows such as Home Building and Renovating Show, and simply just doing the work and getting hands on experience.

When researching insulation methods, I came across an amazing source https://woodfibreinsulation.co.uk/courses 
Spoke to Chris Brookman – Back to Earth’s founder, very helpful guy and I really wish we could of made a financial case of using that product as it’s so nice to work with, way better than PIR. But check those courses out, even though they are Woodfibre orientated, the fundamentals you learn can be applied to any insulation method (with a couple of changes) so this is a great investment for your time).

I think the biggest takeaway from what I’ve learnt and still learning today is that don’t be scared of trying things, and that the industry is designed to look difficult on purpose but in reality, it’s not that difficult and it all just really boils down to how much time you have to throw into this. 
What method of insulation have you chosen and why?
We’ve had 3 types of insulation methods available to us – Cavity, External, Internal, Floor.
Cavity Insulation - Although the house being around 1930s we have a cavity. However, due to this being an old cavity it relatively filled, plus with the poor jobs done on other properties in the UK and horror stories abundant, we opted not to use this method.
External Wall Insulation – This is by far no doubt the most efficient and cost effective insulation method as it delivers most coverage, quickest, least messy, and massively reduces the issue with thermal bridging, however it does affect the appearance of the house, this is something we very much were against, so this method didn’t tick all of our boxes.
Internal Wall Insulation – This method takes up a significant portion of floor space in the household, detail on the finish is a critical requirement. Since we were stripping all our rooms (eventually!) back to brick, dropping ceiling and floor space wasn’t an issue, we opted to utilise this method.
Floor insulation – On the ground floor we have, mostly, quarry tiles on mud. With the exception of one room which has ½ of the room with suspended flooring. We’ve made a choice to dig up the downstairs floor spaces and insulate using the following subfloor build up - Concrete Pad -> DPM -> PIR Insulation -> DPM -> Wet underfloor heating pipes -> Screed -> Floor finish. For our upstairs rooms we decided not to insulate, however we do get a benefit of small amount of insulation due to our underfloor heating system (more on that later).
What type of insulation have you installed?
Originally, because our house was built using traditional methods of utilising lime, we wanted to use Wood Fibre insulation as it helps with transfer of moisture and still allows the house to breathe as it was intended. We used this method for two rooms, however we’ve hit a significant issue utilising this method, one was cost, and two was the ability to easily obtain the materials at general builder’s merchants, so you’d have to stockpile as the delivery costs were rather lumpy! We don’t really have anywhere to stockpile, and due to builder availability we had a few bags of lime plaster go off, so utter waste of money. 
Instead, we opted to go the PIR route. This material was more readily available to collect as you wished and it didn’t really matter which brand you picked as they all offer relatively same performance. 
Our design is now to use 50mm PIR insulation boards which give us a 0.3 U Value. 

Critical point is to communicate with the vendor of choice, our merchant stocks Ballytherm, to get a calculation on the performance and thickness of insulation based on your wall composition. 
I reached out to Ballytherm, who were super helpful, and generated a performance calculation for us which we used as part of our Building control submission. 

Overall, our walls are made up as such:
Brick 🡪 bonding (flatten our wonky walls) 🡪 PIR 50mm 🡪 20-22mm Battens 🡪 Plasterboard (12.5mm)
This gives us 0.3U value, which was our target. And on average we lose around 85mm – 94mm (bonding dependant) on external walls inside the room. Our original tolerance was 100mm lost in the room, so we are within this budget.

We also could of used insulation which has plasterboard already on it, however we wanted to have a service void, and also we wanted to make sure that when we hang things on the wall we are reducing the puncturing of the water vapour barrier.

What does the process of installing internal wall insulation look like?
We start off by stripping the whole room back to brick, this is a messy task but guarantees that we catch any underlying problems to repair such as lose mortar around bricks, or old plaster being blown. We also drop the ceilings and eventually lift the old floorboards up which had Wood fly attacks over the life span.

Once the room is stripped, we skim the walls flat to make hanging insulation sheets easier. 
Next we use Foam adhesive to spray the perimeter of the sheet and then also zigzag lines on the sheet to bond the panels to the wall. Rinse and repeat making sure that each butted join has a spray of adhesive before the next board is added to ensure no air can get behind the board and cause a thermal bridge which will condense water vapour into water and cause you a headache years down the road.

After the insulation has been hung and has gone off, we go around detailing. This is a critical step, and an investment of minimising issues down the road. We back fill all the dents, punctures, gaps and tape over them with foil tape. We also tape over any board joins.
This creates a continuous water vapour barrier and minimises any risk to air passing behind the board and hitting that cold brick surface.

Once the external wall is lined, we fix 22-25mm battens on the insulation, this allows us the ability to have a service void and minimise puncturing the water vapour barrier. The battens are fixed with nylon sleeved screws straight through insulation into the brick work. Then we hang plasterboard sheets (after fist fix is complete).

What heating system to you use?
After doing numerous hours of research into different Oil/ Gas alternatives to heating we settled on a Nibe Air source heat pump, F2040 16kw model. This comes with 300L hot water cylinder and a 200L buffer tank (this is used as a heat store battery essentially).
We discussed the solution at a trade show and Nibe came across the most professional and efficient solution at the time, as well as with the Automation features we knew we wanted later down the line.

We also decided upfront that where we can we will be putting underfloor heating in with each room having its own zone. We went around the market and used various underfloor companies and were shocked at the costs they were offering. This is really one of those where DIY makes a massive difference. We ended up working with Wunda, we sent the plans for our house with measurements, and they created a design for us for all the pipe runs. This generated a bill of materials which we still use to purchase against. 
The critical piece to this, is installing all of your main items (Manifold/Pumps/Integration into your heating system and wiring) up front, we had our plumbers and electricians do this job for us as the Airsource heat pump was being installed. This contained upstairs manifold hook up and downstairs. 
Now that those elements are in, we DIY install the floor pipes. This method has saved us 1000s. 
Would you recommend an air source heat pump and why did you choose it?
We settled on this heating method because we don’t have gas in our area, and getting Gas or Oil delivered to site is a pain. We also had no working solution at home and needed funding to do all of the other work as well, given that this solution came with Renewable Heat Incentive (RHI) payments it was a no brainer financially.

However, I would never ever put this solution into a property where you are not doing the full insulation and installing any underfloor heating to increase your radiator surface area. Reason being that the system works very differently to a traditional burn hot and short vs burn low and long. And if you have a leaky, uninsulated property your house will just never heat up and you will burn a lot of money on your electrical bills. 

This is the main reasons in the UK that the heat pumps are getting a bad rep. The solution is over promised to everyone. 

If you have gas/oil today and its working, I would 100% recommend just insulating your property, that money is better spend here and will reduce your heating bills the most. Makes a much better investment. Then when your boiler packs in put an alternative energy heat source in place and then benefit from what that offers.

What is the cost and how are you funding this?
As mentioned before, it made financial sense to use the heat pump due to the RHI program. This essentially offsets the financial penalty of an uninsulated home as we are catching up doing the work.

We also used Robert Owen Community Banking Fund for an interest free loan as a capital injection for several things we were doing at our house. Without them, it would have been very difficult to get all the important things off the ground that we needed to get done as they were the fundamental building blocks which we are now working around.

Now that we have big items installed, we are using savings as our “business as usual” room by room work.

NIBE Heating (including water and plumping) - £12K
Underfloor heating (whole house) materials only - £3.2K (this is the opposite to quotes from 5K to 10K we had to install!!)
Insulating room (this includes all work form demolition to construction this works out much cheaper if you can do this simple task yourself, however priced is labour and materials) - £3K-8K

What challenges did you face and any recommendations?
Main challenges have been around the following areas:
Finding decent trades to do the work. There is very little understanding in general building trade on internal wall insulation and the importance of the make up and detail.
Recent material costs, but nothing any of can do anything about this one!
Managing builders/trades, because of lack of trade knowledge on this activity you have to manage this yourself, it therefore pays dividend to know what to look out for and essentially act as your own quality control
Finding builders, you can rely on and trust, this has been the most frustrating one as we’ve spent a lot of time educating their guys, then they lost them or never turn up to finish, you then have to start again. This is a very time consuming and painful activity. This is another reason that if you can really consider doing this job yourself and get labourers in as required. I am not sure why there’s such a shortage of decent builders, but here we are.
Getting ripped off, DO your research, and educate yourself. Don’t let companies pull a fast one on pricing. If you can do a task yourself, even as a test room DO IT. You will know labour and materials required to a degree. You can then speak common terms with the people you are getting pricing from.
There is no how-to guide to help you for your case, so if you want to save money put the time in and understand the job. This will give you a better result and also avoid spending where you don’t need to
Getting RHI payments – The authorities wouldn’t allow us to put RHI claim in as they felt insulation of our house wasn’t complete as per Energy Performance Certificate recommendations (which is the most pointless set of recommendations you can find). Basically because the certificate recommended us to do Cavity insulation we fail the test, but what they failed to grasp was the fact that filling our cavity would actually do more harm than good. The whole point of this cert is to be able to save money, however what they done was make us waste money as we had to pay a structural engineer to come out and write a report on what we said was already factual! Cost us £500, thanks OFGEM.
And finally managing builders/trades – yes that’s on here twice… it really is that much of a pain in the back side!

ANEX A – Photos and videos

YouTube video which was sent to Building Control inspector during lockdown for sign off this is the work the wife and I done all ourselves - https://youtu.be/FgWDJ5Rnx-g

Wifes Instagram with various stages of our house 
Utility room (includes ASHP install) - https://www.instagram.com/stories/highlights/18063267223243088/
En-suite - https://www.instagram.com/stories/highlights/17961189265328377/