Having designed, managed and completed four one-off houses, Stephen Montgomery decided it was time to tackle a renovation project. Little did he know that it would change the course of his professional life…

“Ruth and I have been married for 25 years,” says Stephen. “When we started out we got a plot from Ruth’s parents on the other side of the road from the family farm. It was a long narrow site with a lot of road frontage, and we ended up building four houses on this site, which gave us plenty of house building experience!” While their next project was not a new build, it could almost be qualified as such…

“Ruth’s parents built their family home around 40 years ago, on a magnificent elevated site with views to the Belfast hills to the north and the Mournes and the Dromara hills to the south. They’re both keen gardeners and over the years they used the naturally occurring rock outcrops on the site to act as a foil to their lawn and tree planting scheme. But with their children all away, advancing years and mounting maintenance problems, the house was becoming too much for them to manage. It was a choice between selling and relocating, or us stepping in to create a new home that both could share. We took up the challenge!”

The Challenge

“It was a major renovation project. The house was a fairly conventional suburban type bungalow, of simple rectangular form with a detached garage behind, sited to maximise the views. At some point in its history a covered link had been added to join the house and garage to provide a utility room, and this gave the house the shape of an inverted ‘T’. Across the yard was a farm shed running perpendicular to the front elevation of the house, so I thought there was a possibility to form a courtyard, by linking the house to the shed with a covered archway.”


The project itself lasted five years, from drawing board to moving in, with a lot of time spent waiting for planning approval. “A new draft planning policy statement had just been issued; it was trying to protect against ‘granny flats’ being later turned into separate dwellings. It appeared to be unacceptable to have kitchen facilities in the annex and a separate entrance wasn’t permissible. We had to prepare a case to support the application which demonstrated that the layout proposed was always going to be a part of the main house and that a degree of independence was essential, even for a shared living arrangement like ours. It took a year, but it eventually got approval. We had anticipated that there would be planning issues with the design given that it was a very elevated site visible from the road, but things like ridge height and the scale of the changes to the front elevation were accepted without challenge. The transformation to the house has been quite dramatic, and it really does stand out now, it certainly is striking from a distance! The house is so high up people know it from passing by and it does look nice. I’ve had enquires from strangers coming to the house to ask who designed it, and I say ‘you’re looking at him!’”

The Montgomerys took a phased approach to the build as Ruth’s parents would be living on site throughout. “The design for the project involved adding a new storey to the original house, and extending to the front to increase the size of the lounge and give a better orientation to the main entrance door. The original garage and utility room were to be demolished to make room for a new self-contained ‘granny’ flat, with the main house linked to it and the first floor extending over the top.”

“The design also added a side extension to the main house for a utility room and an extension to the former farm shed to bring it into line with the main house, so that the two could be linked with a covered archway to form the courtyard. The farm shed was redesigned to provide garage space to replace that lost by the demolition. The original site entrance was blind to traffic from one direction and was very dangerous, so we made a new driveway with proper sightlines a priority. Stage one was to put in the new entrance, and from past experience care was taken to make this wide enough for all the construction traffic that would be using it.”

“Ruth’s parents wanted to downsize so this design was a perfect solution, apart from the question of what to do with all their stuff! The next stage was for the farm building to be converted to the garage space, and that’s where they kept the surplus. Stage three was to demolish the old garage and utility room and build the annex from scratch. Our bedroom is above it so we put in a concrete floor to give very good soundproofing, and their space downstairs is completely self-contained.”

Stage four could then begin, which was the refurbishment and extension of the main dwelling. Stephen started off by removing the entire roof structure, and wasted no time in doing so! “I didn’t know how far we would go. The roof went because we wanted to add a floor above. We increased the pitch and ridge heights to make sure that the maximum use of space was achieved, and put on a cut roof with ridge beams throughout. The existing mahogany windows were taken out because the double glazing only had a 5mm gap, the draught sealing was non-existent and they just weren’t performing well. So we were left with a single storey flat base to work from. We gutted the interior but kept the ground floor masonry walls pretty much intact, and we worked on the basis of those. The cavity is only 75mm wide and while it would have been ideal to have it wider to be able to put in more insulation, there was no choice!”

gable endThe man behind the build

“I took a three year career break to complete the build and as project manager the first thing I did, as most self-builders do, is buy a digger, an 8-tonne track machine. It’s the best purchase I’ve ever made! I did all the digger work myself and also used the machine to handle materials. I really did use it every day. In fact, there was very little I didn’t do myself apart from the blockwork, plasterwork and roof covering – there were 25,000 slates in total!”

Stephen designed the house and got his nephew to prepare the CAD plans to his specifications. “I made a Building Notice application to Building Control and agreed construction details with the Building Control Surveyor at each stage. There are still some external works to complete such as ramps and steps so the completion certificate hasn’t been requested yet. We didn’t need any external financing for the project so there was no need for inspections for mortgage stage payments. I did any structural calculations needed for sizing steel and timber, as there was nothing overly complicated about the structural design.” Stephen used the design service offered by manufacturers for the more specialist elements of the build, including concrete floor units, special lintels and underfloor heating layout.

As you might have imagined, his background is in construction, and he’s been at it since he was 10 years of age. “I did a Building Engineering and Management degree after school and worked in the family business until joining Building Control about 17 years ago,” he says. More studying followed, with Stephen getting an MSc in Fire Safety Engineering, before becoming head of Building Control at Newtownabbey Borough Council. “I’m a member of the RICS, the CIOB and the Association of Building Engineers, so I have plenty of background knowledge and experience.” Stephen returned to work from his career break in December 2009 when the build was completed but couldn’t settle into what he refers to as the bureaucratic world of local government, and has since left to start his own business – in the construction sector of course!

“In October 2011, I started my own practice working as a building surveyor, designer and project manager. Having other people’s projects going on has slowed down the overall completion of our own build, with the final phase being the hard landscaping outside. We bought all the paving materials last year when the supplier had a special offer but I’m not sure when I will get it all laid!” Stephen works from home and has been able to incorporate space for a design studio into the build. “On the other side of the arch into the courtyard where we extended the garage we are planning to use the space as an office for me and a work room for Ruth, who is a wedding cake designer and decorator.”

Building envelope

“When we went to build the granny flat, we cleared the topsoil off and were left with a solid rock plateau, only half a metre below the surface. To level it up for building we had to form a foundation on top of the rock using permanent shuttering built in blockwork. This was poured with concrete and reinforced with an anti-crack mesh,” says Stephen.

“On the new build portion of the house, I used medium density concrete blocks outside and low density concrete blocks on the inside, pumping the 100mm cavity with polystyrene bonded bead insulation. In addition, the internal walls were dry lined with 25mm PIR insulation and plasterboard.”

“The new ground floors were constructed as in-situ ground supported reinforced concrete on a radon barrier. The existing house had suspended timber floors, and these were replaced with solid concrete floor slabs, which required 100 tonne of stone and 20 tonne of concrete to be wheeled in by barrow and placed by hand! And there’s a warm roof over the whole thing, as I learned how important it is to have one, from experience on the four previous builds. It gives you a much tighter building envelope.”

200911pl038-1024x682The exterior of the house has been rendered with a proprietary mixture of lime, portland cement and limestone to give a contemporary look, with a few small areas of multi-coloured natural slate cladding to break up the elevations. “I put that on myself,” adds Stephen. “It’s a bit like wall tiling with ‘Z’ shaped tiles of natural slate bonded onto a mortar back. When it is finished it is just like a handbuilt dry slate wall and looks extremely well. We have made the most of it during nighttime hours too by installing LED up and down lighters to highlight the texture of the stone.”

However, a year on, it is apparent that the render will need regular maintenance. “On some elevations, particularly where we have mature trees or vegetation nearby, we have noticed a greenness coming on the render over the winter months. It has turned out to be algae and I have had to spray it with a diluted hypo-chloride mixture, which removes it instantly as if by magic! The render contains additives to prevent algae growth but it doesn’t seem to work on our site – it’s a real pain! I am considering treating it with a waterpoofer as we are high up and exposed to driven rain, meaning the render is damp on the side that faces the prevailing winds. I will discuss it with the render supplier first.”

PVC windows and doors were used for both new and replacement frames; an oak finish was chosen to match the soffit and fascia on the outside and a white colour on the inside. “My brother in law works in the industry so we were able to source exactly what we wanted at the right price.”

The stainless steel staircase was built by a local engineering firm, to Stephen’s concept design. “The staircase has two half flights with a full width landing, and is open riser. The structural strength of the stairs comes from two cranked stainless steel strings for each flight supporting solid oak treads. They are guarded with toughened glass side panels, fixed to the treads, and topped with a stainless steel handrail. Our daughter has reduced mobility and needs a sturdy handrail to grip. It was fantastic to be able to design in some features to make it much easier for her to manage.” There is quite a bit of architectural metalwork in the house, including frameless glass balustrading, balcony guarding, estate fencing and wrought iron gates; all of which was completed by the same engineering company.


“The site is very exposed so I didn’t want trickle vents due to the risk of wind noise. We chose an input air ventilation system; this uses a continuously running fan in a central location to introduce a slight positive air pressure in the house which has the effect of moving air outwards through natural leakage paths such as chimneys and satisfies the requirements of the Building Regulations.”

“We have two independent heating systems, one for the annex and one for us, necessitated by the phased nature of the build. Ruth’s mum had always wanted an oil fired range so we put one in for her, which provides both cooking and central heating. When we saw how much they enjoyed it, we decided to get one too. We use it for central heating and as a secondary cooker. The annex has an open fire but we plan to change this to a small wood burning stove. We have a wood burning stove in our double height living area, which is in a central position in the house. It looks fantastic as it is a really contemporary design and boy, can that thing heat; it can keep about 75% of the house warm on its own without central heating! During the really cold winter of 2010/11 the heating upstairs wasn’t finished, and even though it was -15°C outside, we never noticed! We are burning timber salvaged from the demolition of the existing house and have enough to do us for years to come.”

Stephen did detailed heat loss calculations for each room to determine the amount of heat input required and sized the underfloor heating pipework, radiators and boiler accordingly. “In my experience, this is not always done in detail by installers who will use standard tables instead. The benefits of extra insulation are often ignored so that radiators, and usually boilers too, are oversized and therefore not as efficient. We were able to specify a smaller output boiler than would normally be the case for a house of this size, which will save us money in running costs in the future.”

“There’s underfloor heating downstairs and conventional radiators upstairs but they’re plumbed like underfloor heating: each circuit/radiator is piped back independently to a manifold with individual motorised zone valves. This means that there are no concealed joints in the pipework, and each circuit/radiator is individually controlled by a room thermostat. The system has been set up to provide three main zones – hot water, downstairs and upstairs – for overall programming control, and in addition each room has an electrical thermostat. It allows us to set back the temperature in rooms that are not being used, to turn off the central heating automatically in rooms that are getting enough heat from the stove and to boost the heat in our eldest daughter’s room, where she spends a lot of time studying.”

With rising fuel costs, the Montgomerys now want to reduce their use of oil for heating and plan to use the range for cooking only. That was an eventuality Stephen had already made provisions for: “The heating pipework has been installed to allow a second boiler; we intend to install a large wood burning boiler in a nearby outbuilding. The burner will heat up a store of hot water in an accumulator tank from which the house system will draw when hot water is required for central heating or other uses. The range will then become a backup boiler and allow us to reduce our spend on heating oil!”

“The heating systems within the main house and the annex each have a thermal store installed, which are open vented but provide instantaneous hot water at mains pressure. The system has the advantage of not needing to be installed by a registered plumber under Building Regulations, unlike an unvented system. This was an important feature as I did the installation myself.”

Inside story

“The design and layout of a house is all about how you want to use it,” says Stephen. “It’s especially important to consider where you cook, eat, and relax. These activities must all fit together well and the design can make this happen. Done right it can create a real centre to the home. We wanted to connect the main living spaces – kitchen, dining and family rooms, both visually and physically, and yet still have some delineation between them and be able to split them up for different situations. We have used level changes, glass and double doors to achieve this and it has worked really well.”

“We also designed the house to open up to the outside visually and – weather permitting! – physically. A lot of this comes down to letting the outside light in. We have 26 roof windows in high ceilings, which are really effective at getting light into the centre of spaces. Grouping them together in close coupled arrangements has worked well for us. We didn’t put up any curtains, we believe they’re dust collectors. So it can feel chilly near windows in the winter but our solution is to throw another bit of the old house into the stove and the heat soon rises!”

As for the kitchen, it has a high pitched ceiling, so they used larger height wall units to fit the proportions of the room. “We didn’t want straight lines of cupboards, and in spite of having a traditional range, we didn’t want a traditional country style kitchen! We opted for walnut doors with some glass inset panels, and went for composite worktops. We also managed to get a bit of stainless steel in there, in the plinth to the base units and as a pelmet above the range. The kitchen is a good balance between contemporary and traditional, which is what we like.”

Stephen loves lighting and admits that he did go a bit crazy with LEDs. “Ruth had to tell me to stop at the end! I was putting little lights in everywhere. I haven’t gone for full mood lighting systems but have made sure to have plenty of individually switched lights in each of the main rooms. You can turn on as many or as few at a time as you like, but it did require a lot of extra wiring! In the living room we have four track lights, and four corner lights and the steps have individually controlled LEDs too. At some point I might upgrade the switches to remote controlled radio frequency units, which are starting to become more affordable now. We didn’t go for a lot of home automation but put in a Cat 5e network for the future. Also, every room has a hard wired telephone point but it seems that everything is going wireless now, so all the cabling was perhaps unnecessary.”

So how much did it all cost? “I have kept all the receipts but have never sat down and added it all up – I’m afraid to! As the project was considered a renovation we were unable to claim back any VAT, which added quite a bit. We still have a few things to do so the spend isn’t complete yet. I don’t think I will ever count it all up but you can’t put a price on the satisfaction of doing something like this anyway.”

“A self-build of this scale is all consuming, you don’t have another life when you’re doing it. This past winter, with all the hard work done, we have really started to enjoy the house as a home and it has been worth it!” However, Stephen won’t say if this fifth self-build is to be his last… “With all the family history attached to it, this home is very different to any other we have done – we will be here for a long time, I can assure you of that!”

Site size: 12 acres
House size: 7,200 sqft, including 2,000 sqft garage and future office
Build cost: Estimated £250,000-£350,000

Build spec

Construction type: masonry, medium and low density concrete blocks, with 100mm cavity wall, warm roof
U-values: roof 0.14 W/m2K, floor 0.3 W/m2K, new build walls 0.23 W/m2K, refurbed walls 0.3 W/m2K, windows/doors 1.8 W/m2K
Insulation: beads made of EPS with graphite in cavity walls (new and refurb); 25mm insulated plasterboad (PIR) for walls, 75mm PIR insulation board in floor and roof, 150mm glassfibre added in warm roof
Windows: PVC frame, double glazed, 28mm width between panes, argon filled, low-e