Home Insulation Services in Dublin
OS Holding installs attic and roof insulation, external wall insulation, internal dry lining and floor insulation for homes across Dublin. We are a fully insured, CIRI-registered building contractor, and where your works qualify for an SEAI grant we handle the registration and paperwork.
Most homes need one or two of the four, not all of them. The free survey tells you which, and you get a fixed written quotation before any work starts.
Which Insulation Does Your House Actually Need?
There is no single right answer, because the answer depends on how your walls were built. A solid-wall Victorian terrace and a 1990s cavity-wall semi need completely different work, and the wrong choice is an expensive way to achieve very little.
This table covers the situations we are called to most often in Dublin.
| Your property | Usually the priority | Worth considering | Common mistake |
|---|---|---|---|
| Pre-1970s semi or terrace (solid walls) | External wall insulation | Attic at joist level | Trying to pump a cavity that does not exist |
| 1980s–2000s semi | Attic at joist level | Floor insulation | Paying for wall work before the attic is done |
| Apartment | Internal dry lining | — | Assuming external work is an option — it needs management company approval |
| Bungalow | Attic — the roof area is large relative to the floor area | External wall, floor | Underestimating how much is lost through a big roof |
| Attic being converted to a room | Rafter-level insulation | — | Joist-level insulation alone, which will not meet regulations for a habitable room |
| Cottage or protected structure | A breathable internal build-up | Attic | Sealing an old building tight and causing damp |
If you are not sure which row describes your house, that is exactly what the survey is for.
Attic & Roof Insulation
Two different jobs that people usually call the same thing.
Joist-level insulation lies across the attic floor and keeps heat in the rooms below. In most Dublin houses it is the cheapest worthwhile upgrade available, and it is the one that pays back fastest.
Rafter-level insulation follows the slope of the roof instead. This is what you need when the attic is becoming a room, because the insulated envelope has to move up to the roof line to make the space habitable.
One thing worth knowing before you board an attic for storage: the boards must sit on a raised platform above the insulation, not directly on top of it. Insulation squashed flat under floorboards stops working, and correcting it later means lifting everything you have just laid. It is the single most common attic problem we are called out to fix.
If you are planning to convert rather than just insulate, see attic conversions in Dublin.
External Wall Insulation
External wall insulation — often called wrapping — fixes insulation board to the outside face of your walls and finishes it with render. For a solid-wall house with no cavity to fill, it is the largest single improvement available, and it treats the whole wall rather than leaving cold bridges at the corners.
Because the work happens outside, you keep your internal floor area and you can stay living in the house throughout. The trade-offs are on the outside: eaves and roof overhangs may need extending, window sills and reveals have to be dealt with, downpipes and vents come off and go back, and on a semi or a terrace there is a junction with your neighbour’s wall that needs a sensible detail.
External insulation changes the external appearance of the property. That is straightforward for most houses, but a protected structure or a property in an Architectural Conservation Area needs permission first. We flag anything relevant during the survey so you know where you stand before committing.
Older solid wall houses are where the need is greatest: 26.7% of BER rated homes built before 1978 are rated F or G, and 86.6% of every F or G rated home in Ireland was built before 1978, per the CSO figures in our period and older homes statistics for Ireland.
Internal Wall Insulation & Dry Lining
Where wrapping the outside is not possible, insulated plasterboard fixed to the inside face of the external walls does much of the same job. This is the usual route for apartments, for protected structures, for mid-terrace houses where only the front and back are exposed, and for anyone who wants to phase the work one room at a time rather than do the whole house at once.
It is less disruptive to the outside of the building and it can be done selectively — the coldest rooms first. What it costs you is a small amount of floor area, and the fact that skirtings, sockets, switches, radiators and curtain fittings all have to come off and be reinstated afterwards. Rooms need to be cleared while the work is underway.
Done properly, internal insulation also needs the right approach to vapour control and ventilation. An older building that is sealed up without thought about where moisture goes will develop condensation problems it never had before, which is why we survey rather than quote blind.
Moisture is already a national problem: 21.2% of people in Ireland lived with damp, a leaking roof or rot in 2023, the fourth highest share in the EU, per the Eurostat figures in our damp, mould and radon statistics for Ireland.
Floor Insulation
Floors are the most commonly skipped part of a retrofit, and in older Dublin houses with suspended timber floors they are a real source of cold and draughts. Insulating between the joists from below, where there is access, or from above as part of a floor replacement, removes a source of discomfort that people often misattribute to their windows.
Floor insulation makes most sense when the floor is coming up anyway — during a renovation, a new kitchen, or a flooring replacement. Coordinating the two saves doing the same disruption twice. If you are already planning new floors, see our flooring and tiling work.
Spray Foam Insulation
Spray foam is one option among several for roof spaces, and it suits some structures well and others poorly. It is worth reading about separately before deciding, particularly if you may sell or remortgage the property in future, as lenders take differing views on it.
Full detail is on our dedicated page: spray foam insulation in Dublin.
Grant demand is at record levels: SEAI processed 29,000 applications in the first quarter of 2026, up 96% year on year, and 58,000 home energy upgrades were completed in 2025. Our home energy and retrofit statistics for Ireland tracks the grants, BER ratings and demand figures with their sources.
SEAI Grants
Attic insulation, wall insulation and other energy upgrades are supported by SEAI grants, and a good portion of the homeowners who contact us are trying to work out what they qualify for before they commit to anything.
The essentials are these. Grant work has to be carried out by a contractor registered for the relevant measure, the property normally has to have been built and occupied before a qualifying date, and a BER assessment is part of the process. Grant amounts and eligibility rules are set by SEAI and are revised from time to time, so we will not quote figures here that may be out of date by the time you read them — check the current rates directly with SEAI, or ask us at survey and we will tell you what applies to your specific job.
What we can tell you is that we handle the registration and paperwork side rather than leaving it with you.
What a Survey Involves
Before we recommend anything, we look at the house. The survey is free and carries no obligation.
1. We assess what is already there
Existing insulation and its condition, how the walls and roof are actually built, ventilation, and signs of condensation, damp, mould or timber decay. Insulating over an unresolved damp problem makes it worse, so this comes first.
2. We tell you what is worth doing, and what is not
Including the order to do it in. Some measures make others redundant, and some are far better value than others in a given house. If the honest answer is that one modest job would get you most of the benefit, that is what we will say.
3. You get a written, fixed quotation
Setting out the scope, the materials and the price, with the SEAI grant position spelled out where it applies.
4. We carry out the work
With a dedicated project manager as your single point of contact, and workmanship and material warranties as set out in your contract.
Why Homeowners Choose OS Holding
- Fully insured building contractor
- Registered with the Construction Industry Register Ireland (CIRI)
- Member of the National Guild of Master Craftsmen and the Construction Industry Federation
- Free survey and fixed written quotation, with no obligation
- Dedicated project manager on every job
- SEAI grant registration and paperwork handled for you
- Workmanship and material warranties as per contract
Insulation is often only one part of what a house needs. Because we are a full building contractor rather than an insulation-only installer, we can carry out the insulation as part of a wider house renovation, an extension, or an attic conversion — one contractor, one schedule, one point of responsibility.
Areas We Cover
We install insulation for homeowners across Dublin city and county, including Ranelagh, Rathfarnham, Terenure, Milltown, Sandymount, Ringsend, Marino, Clontarf, Howth, Glasnevin, Finglas, Ashtown, Drimnagh, Ballinteer, Leopardstown, Harold’s Cross, Swords and Balbriggan, along with the surrounding commuter belt in Kildare, Meath and Wicklow.
If you are not sure whether you are inside our area, ask — we will tell you straight away.
View Our Recent Projects
OS Holding completes a wide range of residential building and renovation projects throughout Dublin, including home renovations, extensions, attic conversions, kitchens, bathrooms, and insulation work.
If you’re considering improving your home’s energy efficiency, we invite you to browse our gallery to see examples of our workmanship across a variety of residential projects.
House Insulation Dublin FAQs
How do I know which type of insulation my house needs?
It comes down to how your walls were built. Houses built before roughly the 1970s usually have solid walls with no cavity, which points towards external or internal wall insulation. Later houses generally have a cavity and a different set of options. Almost every house benefits from attic insulation first, because it is the least disruptive and the best value. The free survey establishes which category your house falls into rather than guessing from the age alone.
What SEAI grants are available, and do you handle the paperwork?
Attic and wall insulation are both supported by SEAI grants. The work must be done by a contractor registered for that measure, the property normally needs to predate a qualifying year, and a BER assessment forms part of the process. Grant rates and rules change periodically, so check the current figures on seai.ie or ask us at survey. We handle the registration and paperwork rather than leaving it with you.
My walls are solid. Should I insulate inside or outside?
External insulation treats the whole wall, avoids cold bridges, keeps your internal floor area and lets you stay in the house while it is done, but it changes the outside appearance of the property. Internal dry lining is less disruptive externally and can be done room by room, but it costs you a little floor area and means removing and reinstating skirtings, sockets and radiators. Apartments, protected structures and mid-terrace houses often have the decision made for them.
Can I insulate my attic if I also want to board it for storage?
Yes, but the boards have to sit on a raised platform above the insulation rather than directly on top of it. Insulation compressed under floorboards stops doing its job. This is the most common attic mistake we are asked to correct, and it is far cheaper to build the platform at the outset than to lift a finished floor later.
Will insulating my house cause condensation or damp?
It can, if it is done without regard to ventilation and moisture. Making a house warmer and more airtight changes where moisture goes, and an older building sealed up carelessly can develop problems it never had. This is why we survey for existing damp, mould and timber condition before quoting, and why the ventilation strategy is part of the recommendation rather than an afterthought.
Do I need planning permission for external wall insulation?
For most houses it is not required, but external insulation does change the appearance of the property, and protected structures and properties in Architectural Conservation Areas do need permission. We identify anything relevant during the survey so you know the position before committing to the work.
How long does the work take and do I need to move out?
It depends entirely on which measures you are having done and the size of the house. Attic insulation is usually the quickest and least intrusive. External wall insulation happens outside, so you can stay living in the house throughout. Internal dry lining is the most disruptive internally, because rooms need to be cleared and finishes reinstated. We give you a schedule with the quotation.
Can insulation be done as part of a renovation or attic conversion?
Yes, and it is usually the sensible time to do it. If floors are coming up, walls are open or the attic is being converted, the insulation work is far cheaper and less disruptive done at the same time. As a full building contractor we can carry out both under one contract and one project manager rather than coordinating separate trades.
Request Your Free House Insulation Survey
Whether you’re looking to reduce heat loss, improve comfort, or include insulation as part of a wider renovation, OS Holding is here to help.
We’ll assess your property, explain the insulation options available, and provide a free, no-obligation quotation based on your home’s specific requirements.
With a fully insured team, dedicated project management, recognised industry memberships, and a straightforward consultation process, you can move forward with confidence.
Commitments for Project
As a top building contractor, our team of expert tradesmen and managers is dedicated to ensuring the seamless completion of your project. Particularly, we will guide you through the process and ensure transparency to help you make informed decisions.
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