Find out how a 1950s semi-detached house was transformed into a family home in this costed extension project in Co Dublin.
In this article we cover:
- Finding the property and how they spotted its potential
- Cost breakdown of both professional fees and build components
- Design process and how it was affected by the budget
- Securing planning permission
- How the project was managed
- Tips to others thinking of a similar project
- Kitchen design process
- Choice of external finishes
- Choice of internal floor finishes
- Converting the garage into office space
- Futureproofing measures
- Interior design process
- Choice of windows to avoid overheating
- Troubleshooting: issues with liquid screed, steel beam placement and steps to the garden
- Impact of insulation on room sizes
- Timeline, specification and suppliers
- Before and after floor plans
Derek and Lindsey’s first home together was a cosy three bedroom townhouse, close to the city. “It was the perfect size when it was just the two of us, but as our family grew, the space quickly became impractical,” explains Derek
What used to be enough room for living, dining and the occasional work-from-home day soon became cluttered chaos with the addition of kids and a full-time work from-home setup during the pandemic. “With just one room downstairs it became clear that we needed more space—both for living in and for our sanity.”
That realisation led to them buying a tired, 1950s semi-detached house. “It needed extensive work,” says Derek, “including rewiring, new windows and plumbing, but it allowed us to create a home that would give us more room, more privacy and a design that would grow with us.
House size before: 150sqm including garage
House size after: 190sqm
Bedrooms: 4 plus attic conversion
Plot size: 510sqm
Build cost: €450k
BER before: E2
BER after: A3
Heating system: Air to water heat pump
Ventilation: Demand controlled mechanical ventilation
Build method: Concrete block
Must-haves
They approached the design process with a clear picture of what they wanted, handing their architect a detailed brief of both “must-haves” and “nice-to-haves.” High on the priority list was an open-plan extension at the back of the house, with a kitchen, dining and living area that would act as the heart of the home. “We also hoped for a separate living room, a utility room, an office—essential in the post pandemic world—and a playroom for the kids.”
Budget constraints kept some dreams, like a walk-in wardrobe and the in-frame kitchen, on hold, but the couple stayed focused on their key priorities. The couple’s style preferences played a major role in shaping the design of their new home.
“Our taste runs somewhere between modern and classic, and we wanted our home to reflect that,” says Derek. “From the beginning, we envisioned a mix of clean, contemporary lines and traditional materials. One standout design decision was to opt for a flat roof on the extension, despite the architect’s initial proposal of a pitched roof. We felt the flat roof would reflect the modern feel we were going for.”
Choosing the right materials was equally important. “We were drawn to natural elements like brick and wood, which we felt would add warmth to the space. In the end, we went with a honey coloured brick extension. The colour of the brick reminded me of the cottages and buildings that we’d seen and admired when we visited the Cotswolds in the UK. I loved the earthy, welcoming tone.”
The extension features a large picture window and a window seat in the kitchen area that maximises natural light. “It also creates a connection between the indoors and the garden—another goal of ours,” adds Derek
The planning permission process for the renovation and extension project was relatively straightforward. “There were a few minor conditions imposed by the planners, mostly relating to the roof and dormer,” explains Derek. “They removed the roof lights from the front elevation and requested that the rear dormer materials fit better with the surrounding area.“
All in all, we didn’t encounter any major roadblocks. The approval came through with minimal fuss, allowing us to move forward without significant delays.”
Team triumph
The project’s success came down to teamwork, says Derek. “We worked closely with our architectural technologist, Joe Fallon, who provided a detailed technical report, as well as with Luke and from the practice. We remained hands-on throughout the process. By staying involved and making decisions quickly when the builder needed input, we kept the project on track. “
A quantity surveyor (QS) also helped us navigate the financial aspects providing cost estimates and helping us stick to our budget. Our builder, recommended by our neighbour, kept the construction running smoothly and on schedule.”
The kitchen was a central focus in the renovation project, integral to the open plan living area at the back of the house. From the outset, Derek and Lindsey knew they wanted a kitchen that wouldn’t date quickly.
They enlisted the help of kitchen designer Colin Maher, working closely with his then designer Anna Rock, to bring their vision to life. One of the significant decisions was to choose a classic shaker style kitchen for a touch of timeless elegance in the space. Storage was a top priority, with the couple insisting on ample cabinetry to ensure everything had its place. The finished kitchen includes a large island with built in storage, and a composite material countertop selected for its durability and good looks. A nice feature is the open shelf that extends between the upper cabinets over the sink, which they felt added a distinctive and homely design element to their new kitchen.
The structural elements of the project were carefully planned and executed to ensure the new spaces were both functional and visually pleasing. “
We clad the extension walls with brick slips and the roof with zinc. The slips gave us the look we wanted while also saving money, as they required a lot less mortar, which is surprisingly expensive.”
The flat, 25sqm extension roof is covered by a mechanically fixed membrane. Two roof lights were installed to bring in natural light and brighten the open plan space. For the flooring, the couple chose different materials based on the function of each room. Most of the ground floor is finished with engineered wood, the utility room and the bathrooms are tiled while the playroom is finished with laminate flooring.
To create the necessary office space, the existing, attached garage, which spanned from the front to the back of the house, was divided into two areas by a stud wall to create an office and playroom. “The office is small, approximately 2m x 3m, but it is very functional,” says Derek. “Lindsey was insistent that the playroom would take up most of the space, and that decision makes sense – the kids use it all the time and their toys and playthings can be stored in there.
“ We were unsure about how to use the converted attic. Currently, it serves as a flexible, multipurpose space, including a guest room and an additional office for when Lindsey works from home. As our children grow older, we may consider turning it into a teen bedroom or a music room to meet our changing needs.”
“Energy efficiency was a key concern for us. We installed a heat pump system although it required some time and effort to get it fully optimised.”
To prevent overheating, they added a demand-controlled mechanical ventilation system, maintaining comfort and air quality.
The couple have prepared for a future electric vehicle charging station, although they don’t yet own an EV, showing their commitment to future proofing their home.
The interior design process was gradual. “We booked a consultation with interior designer Ella early in the project to help us with the look and feel of our open plan room. Since moving in, we have slowly added pieces that complement the calm, neutral aesthetic we were aiming for,” explains Lindsay. “We focused on natural materials and a timeless style, so the space felt elegant and cohesive. We bought Ella back to design our living room in full when we couldn’t face any more decisions!”
Derek and Lindsey admit they found the bathrooms to be the most challenging areas to consider and make decisions on, due to all the “moving parts” involved. “We went for different themes and styles, rather than one single look,” says Lindsey.
“The downstairs toilet features traditional tongue and groove panelling on the lower half of the wall and wallpaper on the top. While the ensuite bathroom has a more contemporary feel with cement tiles and black hardware.”
Glazing was another important consideration. They chose double glazing at the rear and triple glazing at the front of the house. They also installed a special “solar control glass” on the ground floor windows at the sunny rear of the house. This was done to address the significant solar gain they were expecting due to the south-facing orientation of the extension. The glass helps reflect the sun’s heat while still allowing natural light to come through.
Challenge conquered
No self-build project is without its challenges, and this renovation was no exception. The couple faced several issues during the build that required
adjustments and additional costs. One of the main challenges was the liquid screed over the underfloor heating, which took much longer to dry than expected, delaying the installation of the flooring and kitchen. To address the moisture issues, a waterproof membrane was added, incurring an unexpected cost.
“It got to the point that, with our previous house now sold we had to split up as a family and live apart in our respective parents’ homes until the screed was dry enough to lay the flooring. This was a particularly stressful time for us.”
The steps into the garden were another issue, as the couple felt they were too steep, despite meeting regulations. “Especially for our older parents when they come to visit, as they’re not comfortable using the steps. I’ve already tripped up on them, and we have to watch our children like hawks when they are outside.”
They are now looking to modify the steps to make them safer and more accessible. “It’s an an issue we should have pushed harder on earlier in the process, rather than deferring to the contractor’s assurances that the steps met regulations.”
Lindsey, in particular, felt they should have been more insistent on the step design, as their concerns proved valid once the steps were installed.
The high levels of insulation also had an unexpected impact on room sizes, particularly in smaller spaces like the utility room. This led to a situation requiring a redesign of the space and removal of a new window, in order to fit the appliances and heat pump.
Additionally, there was a misunderstanding between the structural engineer, architect and builder egarding the placement of a steel beam. This resulted in a pillar protruding into the kitchen space, which the kitchen team had to find a way to conceal within the design.
Despite these issues, they’ve come through the process with a home they truly love—one that meets their needs, both now and for the future. “Looking back, we’re thrilled with how the project turned out. Our new home provides the space, functionality and connection to the outdoors that we always wanted. The xperience has been a learning curve, but one that we wouldn’t trade. It’s a space that allows our family to thrive, and for that, we couldn’t be more grateful.
Cost breakdown (including VAT)
Architect fees covering concept designs, planning permission and building control submissions: €21.5k
Quantity surveyor: €5k
Project Supervisor Design Stage: €900
Sanitaryware: €13k
Windows: €33k
Electrical works: €36k
Mechanical and plumbing works: €40k
Landscaping (so far): €11k
Interior designer: €900
Q&A with Derek
What is your favourite design feature?
Our favourite part of the renovation is definitely the open plan kitchen, dining and living room. It’s the most functional space, and it’s where we spend the most time as a family. For me, the kitchen stands out as we put a lot of effort into its custom design, and I’m really pleased with the classic style we achieved.
What would you change or do differently?
Looking at our master bedroom, Lindsey and I feel it’s a bit tight for space. If we had had the budget, we might have reconfigured the first floor layout to make the master bedroom larger. As for the decision making process, we wish we had received more guidance on the order in which decisions needed to be made throughout the renovation. The fast pace of the 10-month project often left us scrambling, and a bit more notice on what was coming next may have made things less stressful.
What surprised you?
Lindsey: I found it unexpectedly difficult to work out the bathroom designs. With all the different components and decisions involved, on a small budget, it was a lot more complex than I initially thought.
Derek: I was surprised by how much the insulation actually reduced the dimensions of some rooms, particularly the smaller ones like the utility room. It was something I hadn’t fully anticipated. I was also surprised by how expensive it
was to replace the boundary walls (which were flagged as structurally unsafe during the initial survey). They ended up taking up a significant portion of our contingency budget.
What single piece of advice would you give to a budding self-builder?
Surround yourself with a strong team: I’d say the most important thing is to have the right professionals on your side—like a good architect, contractor and quantity surveyor (QS). Since most people aren’t experts in renovation projects, having a reliable team to guide you is absolutely invaluable.
Derek’s Top Tip
Be very careful with the PC Sums. PC Sums are estimates builders give you for a part of the build, usually things like the kitchen. I found it’s really easy to get tempted to upgrade finishes and materials, which can quickly blow your budget. I’d recommend being disciplined and sticking to the essentials to avoid overspending
Spec
Walls: mineral wool insulation between studs 100mm, U-vaule from 0.20W/ sqmK to 0.15W/sqmK;
External walls: 125mm PIR insulation, U-value from 0.13 W/sqmK to 0.15W/sqmK
Roof: 150mm fibreglass insulation between joists, U-value from 0.13 W/sqmK to 0.15W/sqmK
Floor: 200mm quilt insulation between floor joists (for Attic), U-value 0.12W/sqmK
Windows: 1.4 W/sqmK overall U-value on double glazed and 0.94 on triple glazed and 1.1 on slider aluclad. Alucad triple glazed on the front and double glazed on the back; Windows on the bottom floor at the back of house have solar glass, argon filled. RAL front inside 9010; RAL front outside 7044 (Silk Grey); RAL back inside 9010; RAL back outside 7016 (Anthracite).
Suppliers
Contractor
Darrin Fagan, First Class Building and Carpentry, Santry, mobile 086 105 1244
Architect
Luke Kuchta of Joe Fallon Design, joefallon.com
Quantity Surveyor
Mark Hanton of HantonQS, Wexford, mobile 087 241 5342
PDSP
Lory Higgins, Wexford, mobile 087 9087833
Kitchen
Colin Maher Kitchens, colinmaher.ie
Furnishings
Sofa: Sofa So Good, Navan Co. Meath, sofasogood.ie
Interior Joinery
John Byrne Premier Kitchens, Kilbarrack, Co Dublin, premierkitchens.ie
Dining Table, chairs and Bar Stools
Kian Furniture. Kylemore Dublin, kian.ie
Interior Design
Ella Webb, House Iconic, houseiconicinteriors.com
Hicken Lighting, hickenlighting.com
Windows
Vindr VS, vindrvs.com
Sanitaryware and tiles
The Stone Rooms, thestonerooms.ie
House of Tiles, houseoftiles.ie
Photography
Luke Kuchta
NI calling ROI prefix with 00353 and drop the first 0
