Getting an SEAI Attic Insulation Grant? Fix These Roof Problems First

With heating bills on everyone's mind in November, plenty of homeowners in Dublin City and Wicklow are looking at the SEAI attic insulation grant. It is a sensible upgrade: SEAI's own homeowner's guide to attic and rafter insulation says an uninsulated roof can account for 20-30% of a home's heat loss.

But insulation is only as good as the roof above it. Laying a thick new layer of quilt under a roof that leaks, or blocking the eaves vents on an attic that already struggles with condensation, can turn a grant-funded upgrade into a damp problem. This guide explains what the grant covers today, and which roof problems are worth sorting before the insulation contractor arrives.

What the SEAI attic insulation grant pays (November 2026)

SEAI pays a fixed amount per house type. These are the figures on the SEAI attic insulation grant page and in the Homeowner Application Guide at the time of writing:

*The higher grant is for first-time buyers who bought on or after 1 January 2025, homeowners receiving qualifying Department of Social Protection payments, and landlords with an active HAP tenancy or RAS arrangement.

The main conditions SEAI lists:

• The home must have an MPRN and have been built and occupied before 2011.
• The work must be done by an SEAI registered contractor.
• You must have grant approval in place before work starts.
• Homes that already received an attic insulation grant at the same MPRN are excluded.
• Apartments only qualify if they are top-floor or lose heat through the roof to the outside.
• A post-works BER is part of the process.

Grant values and rules change, so always check the SEAI page before you apply. Note that the grant covers the insulation work. Roof repairs are a separate job and are not part of the SEAI measure.

Why the roof should be checked first

Insulating at ceiling level keeps heat in the rooms below, which is the point. The side effect is that the attic itself becomes colder. SEAI's guide points this out when it explains why water tanks and pipes need lagging afterwards.

A colder attic is less forgiving:

• Small leaks stop drying out. A drip from a slipped slate that used to evaporate in a warm attic now soaks into new insulation and stays there.
• Condensation risk rises. Warm, moist air from the house meets colder timbers and felt. Without good ventilation, it condenses. SEAI warns that long-term condensation in the roof space can rot structural roof timbers.
• Problems are harder to see. Once a thick layer of quilt covers the ceiling joists, stains on the plasterboard and wet timbers along the wall plate are much harder to spot.

That is why it pays to have a roofer look at the roof, from the outside and from the attic, before you book the insulation.

Roof problems to fix before insulating

1. Active leaks and old water stains

Look for brown rings on ceilings, damp patches at the top of walls, or staining on the underside of the felt and on rafters. If you are not sure whether a stain is from the roof, plumbing or condensation, our guide to telling ceiling stains apart will help. Any active leak should be traced and repaired first, whether it is a slipped slate or tile, a cracked ridge tile or failed flashing.

2. Torn or sagging underlay

Many older Dublin and Wicklow houses have bitumen felt under the tiles that has torn, sagged or become brittle, especially near the eaves. Daylight through the felt, felt hanging down into the attic, or dust and debris lying on the old insulation are signs it needs attention. See our roof underlay and felt guide for what can be repaired and when a bigger job is needed.

3. Blocked or missing eaves ventilation

SEAI's guide says eaves ventilation openings must be left unblocked after insulation, so air can pass between the insulation and the felt. Its list of questions for contractors also asks whether a minimum 50mm gap between the insulation and felt will be kept.

Before new insulation goes in, check that:

• the soffit or eaves vents are not painted over, blocked by old insulation or missing altogether;
• there is room for eaves trays or ventilation spacers where the rafters meet the wall plate;
• an extractor fan is not venting into the attic instead of to the outside.

We explain how insulation can block airflow in more detail in our post on attic insulation and roof ventilation.

4. Signs of existing condensation or mould

Black spotting on the underside of the felt or on the sarking boards, rusty nail tips, or water droplets on cold mornings all point to a ventilation problem that already exists. Adding more insulation without fixing it usually makes it worse. Our attic condensation checks cover the common causes.

5. Damaged fascia, soffit and gutters

Rotten fascia boards and overflowing gutters can push water into the eaves, exactly where new insulation meets the wall. If your gutters overflow in heavy rain or the fascia is soft, it is worth sorting this at the same time. Our guide to fascia and soffit repairs explains what to look for from the ground.

6. Rotten or damaged timbers

Wet rot at the wall plate, split rafters or timbers that have been cut for old pipes or chimneys should be assessed before they disappear under insulation. Our post on sagging roof warning signs covers when a roof needs a structural check.

Dublin City and Wicklow homes: what we often see

• Victorian and Edwardian terraces in Dublin City often have slate roofs with no underlay or very old felt, shared chimney breasts and limited eaves ventilation. Small leaks around chimneys and party walls are common and worth fixing before insulating.
• 1950s to 1980s semi-detached houses in the suburbs frequently have original felt that has sagged at the eaves, plus old insulation that is compressed or pushed into the eaves and blocking vents.
• Homes in exposed parts of Wicklow, on higher ground or near the coast, get more wind-driven rain. Ridge, verge and flashing details are worth checking because a small leak can go unnoticed for months once the attic is cold.

Other things to agree with your insulation contractor

SEAI's guide sets out what to expect from a grant-funded installation. Before you sign, ask your registered contractor to confirm:

• the insulation will reach the required U-value of 0.16 W/m²K at ceiling level (or 0.20 W/m²K for rafter insulation);
• water tanks and pipes will be insulated, so they do not freeze in a colder attic;
• a permanent walkway will be fitted to reach the tank and other equipment;
• the attic hatch will be insulated;
• downlighters will have enough clearance so they do not overheat;
• eaves ventilation will be kept clear, with the 50mm gap to the felt.

If you also have a dormer, attic room or flat-roof extension, ask how those areas will be dealt with, as they may need a different approach.

A simple order of work

Getting the roof checked first does not slow the grant process down. You can do it while you collect insulation quotes.

Safety first

Please do not climb onto the roof to check it yourself. From the ground, binoculars or a phone camera on zoom are enough to spot missing tiles, sagging gutters or damaged ridges. In the attic, only step on joists or a boarded walkway, use a torch, and stay off the plasterboard between the joists. If access is awkward, leave it to us.

Book a pre-insulation roof check in Dublin City and Wicklow

Perfect Roofing works across Dublin City, North Dublin, South Dublin, Lucan, Bray, Wicklow, Naas and nearby areas. If you are planning SEAI attic insulation, we can check the roof, felt, ventilation, fascia and gutters first, and carry out any repairs so your new insulation stays dry and does its job.

Contact us by WhatsApp, call 083 066 3462, or email hi@perfectroofing.ie.