Floored attics and storage
Insulating a floored attic
You can keep a floored attic and still get the SEAI grant. The boards come up, or a raised deck goes on legs above the new insulation, so the wool reaches about 300 mm without being squashed, with 50 mm of air left under the boards. For a big storage area, insulating at the rafters can make more sense.
The floor is the part that adds time and cost. Here's how it's done, and what to ask for in the price.
Free, no obligation. One SEAI-registered contractor prices it, not five.
- €2,000SEAI attic grant for a detached house
- €2,500at the higher rate
- €300 to €600typically left to pay on a semi-D
- 300 mmof wool: what SEAI's standard takes
Can it be done
Can you insulate a floored attic?
Yes. The insulation goes under the storage area, not on top of it, and it can't be squashed. Compressed wool loses much of its effect, and SEAI's homeowner's guide warns that things stored in the attic can compress the insulation. So the boards are lifted, the wool laid to full depth, and the floor relaid higher.
The options
What are the options for a floored attic?
| Option | What happens | Suits |
|---|---|---|
| Raise the floor | Boards lifted, wool to about 300 mm, the floor relaid on raised legs or new joists with 50 mm of air under it | Most floored attics with headroom to spare |
| Thinner board under the storage | A high-performance insulation board under the floored part, where height is short | Low attics, small storage areas |
| Insulate the rafters instead | The roof slope is insulated, so the whole attic stays warm and the floor can stay | A large storage area, or a room you use |
| Leave the floored part out | Only if it's 15% or less of the heat-loss roof and the contractor records why | A small, hard-to-reach section |
Rafter insulation has its own U-value, 0.20, and ventilation rules: see roof insulation.
Clearing it
Who clears the attic before it's insulated?
Usually you do. Everything stored up there has to come down so the boards can be lifted. SEAI asks contractors to price clearing the attic for people who can't do it themselves, so ask if you need it.
When the storage goes back, keep it to the raised area. SEAI suggests putting storage over rooms like the bathroom rather than the living room, and keeping it to a minimum.
The quote
What should the quote say for a floored attic?
- Whether the boards are lifted and relaid, or a new raised deck is built, and how big it is.
- The depth under the floor and the U-value reached: 0.16 W/m²K for the grant.
- The 50 mm air gap under the boards.
- The walkway to the tank, the hatch, and the tank and pipe lagging.
- Clearing and putting back stored items, if you want it done.
- VAT, stated.
The cost
Does a floored attic cost more to insulate?
Yes. Lifting and raising the floor is extra work on top of the insulation. SEAI's grant doesn't change: €2,000 for a detached house, €1,500 for a semi-D, €1,400 for a mid-terrace and €1,100 for an apartment. See what attic insulation costs.
Grant check
Your attic grant and what's left to pay
Two taps: your home, and which rate fits you. The answer is SEAI's fixed grant and its own median cost for the job.
Your SEAI attic insulation grant
€1,500
- SEAI median cost, Jan to Jun 2026
- €2,101
- Left to pay at the median
- €601
SEAI's fixed grant for a semi-d or end of terrace at the standard rate is €1,500. SEAI's median cost for attic insulation on a semi-d or end of terrace from January to June 2026 was €2,101. €2,101 less €1,500 leaves about €601. Our sum; your quote can be higher or lower.
Send this for a real priceHow this is worked out
The grant is SEAI's fixed amount for that home type and rate, as Citizens Information lists it. The median cost is SEAI's own figure from grant-funded attic jobs completed between January and June 2026; the PDF doesn't say whether VAT is in. Left to pay is the median less the grant, our sum. The home must have been built and lived in before 2011, the contractor must be on SEAI's register, and SEAI must approve the grant before work starts. It's an estimate, never a quote.
Your grant
Your attic grant and a price, in 4 taps
Tap your home, when it was built, what's in the attic now and who you are. Then leave your number and one SEAI-registered insulation contractor who covers your area rings you to look at the attic and price it in writing.
FAQ
Questions people ask
Can you get the attic insulation grant if the attic is floored?
Yes. The floor is lifted or raised so the insulation reaches the standard underneath it. The grant is the same fixed amount.
How much gap should there be under attic boards?
50 mm of air between the insulation and the boards.
Can I put insulation on top of my attic floor?
Not for the grant. The insulation has to be at the ceiling level, under the storage, or at the rafters.
My attic was too full to insulate under the Warmer Homes Scheme. Can I try again?
Yes. SEAI says an attic that couldn't be done before because it was floored or full may qualify once it's cleared. See free attic insulation.
Keep reading
Related guides
- How thick should attic insulation be?300 mm, 200 mm, blown wool or boards: what reaches SEAI's standard.
- Attic insulation costSEAI's median cost by home type, before and after the grant.
- Roof and rafter insulation grantRafters, rooms in the roof and flat roof extensions: the whole-roof rule.
- Condensation after insulationWhy a colder attic gets damp, and the ventilation SEAI asks for.
- Free attic insulationThe Warmer Homes Scheme: who gets it for nothing, and the wait.