How to Choose an Insulation Contractor in Ireland

Getting This Right Matters

The insulation material is important, but the contractor doing the work matters just as much. Poor installation can reduce the effectiveness of insulation by 25% or more. Badly fitted cavity fill can cause damp. Improperly sealed spray foam can create moisture problems. Rushed external wall insulation can crack within a few years.

None of this is meant to scare you. Most insulation contractors in Ireland do good work. But knowing what to check helps you tell the difference.

The Non-Negotiable: SEAI Registration

If you want to claim an SEAI grant (and you almost certainly do), your contractor must be on the SEAI’s register of approved contractors. This is non-negotiable. No SEAI registration, no grant.

You can check the register on the SEAI website. Search by county, measure type, and contractor name.

SEAI registration means the contractor has met minimum standards for training, insurance, and quality. It’s a baseline, not a guarantee of excellence, but it weeds out the untrained and uninsured.

What if a contractor says they’re “in the process of registering”?

Wait until they’re registered before committing. Grant applications require an SEAI-registered contractor from the start. If they’re not on the register when you apply, your grant will be rejected.

What to Check

Insurance

Ask for proof of:

• Public liability insurance (minimum €6.5 million is standard in Ireland)
• Employer’s liability insurance (if they have employees)
• Professional indemnity insurance (covers you if their work is faulty)

Any reputable contractor will have these and be happy to show you the certificates. If they hesitate or say they’ll “send it on”, that’s a concern.

Experience with your type of work

A contractor who specialises in cavity wall injection may not be the right choice for external wall insulation, and vice versa. Ask specifically:

• How many jobs of this type have they done?
• Can they show you completed work nearby?
• How long have they been doing this specific type of insulation?

References and examples

Ask for two or three references from recent jobs similar to yours. Better yet, ask to see completed work in person if possible. External wall insulation is particularly visible, so a drive-by of previous jobs can tell you a lot about the quality of their render finish.

Guarantees

Ask what guarantee they provide on both materials and workmanship. Typical guarantees:

• Cavity wall injection: 25 years on materials, varies on workmanship
• External wall insulation: 10 to 15 years on the system, varies on workmanship
• Spray foam: 25 years (lifetime of the product)

Get the guarantee in writing as part of the contract, not as a verbal promise.

Red Flags to Watch For

Pressure to sign immediately

“This price is only available today” or “We have a gap in the schedule next week” are pressure tactics. A good contractor has enough work that they don’t need to rush you. Get quotes, compare, and decide in your own time.

Unusually low prices

If one quote is dramatically cheaper than the others, ask why. It might be a different material, less coverage, or corners being cut. Cheap insulation done badly is worse than no insulation at all.

No written quote

Every quote should be written, detailed, and itemised. If a contractor gives you a number verbally or on the back of an envelope, move on.

No site visit before quoting

Any contractor quoting for wall insulation without visiting the site is guessing. Cavity width, wall condition, access, obstacles - all of these affect the job and the price. Attic insulation is simpler to quote remotely, but even then, a visit is preferred.

Cash-only payments

Legitimate contractors accept bank transfers, card payments, or cheques. Cash-only requests are a red flag for tax compliance and make it harder to prove payment if a dispute arises.

No mention of ventilation

As covered in our ventilation guide, insulation affects how your home manages moisture. A contractor who doesn’t mention ventilation or ask about your current setup isn’t looking at the full picture.

What a Good Quote Should Include

A professional insulation quote should clearly state:

• The specific measure (e.g., “bonded bead cavity wall injection to all external walls”)
• The material being used (brand and type)
• The area or scope (in square metres for wall insulation, or a clear description for attic work)
• The SEAI grant amount being deducted
• The net cost you’ll pay after the grant
• What’s included (scaffolding, making good, cleanup, BER assessment)
• What’s excluded (ventilation work, sill extensions, damp repair)
• Timeline (start date, expected duration)
• Guarantee terms (what’s covered, for how long)
• Payment terms (deposit, stage payments, final payment)

If any of these are missing, ask. A vague quote leads to surprises.

How to Compare Quotes

Getting two or three quotes is standard. When comparing:

Don’t just compare the bottom line

A €500 difference might be explained by different materials, different coverage, or different inclusions. Compare like for like. If one quote includes scaffolding and another doesn’t, the cheaper one isn’t really cheaper.

Ask what material they recommend and why

Different contractors have preferences. Some swear by bonded bead for cavity walls; others prefer mineral wool or foam. Listen to their reasoning. If they can explain why their recommendation suits your home, that’s a good sign.

Check the SEAI grant figure

All quotes should use the same grant amount. If one contractor claims a higher grant than others, something is off. Grant amounts are fixed by property type, not by contractor.

Consider the whole package

The cheapest quote isn’t always the best. A contractor who charges €200 more but includes ventilation assessment, a thorough site survey, and a clear timeline may save you money and trouble in the long run.

For typical costs to benchmark against, see our home insulation cost guide.

The SEAI Grant Process (What Your Contractor Should Handle)

For individual SEAI grants, the process is:

1. You apply to SEAI online and get grant approval (your contractor can help with this)
2. Your contractor carries out the work
3. The contractor submits the Declaration of Works to SEAI
4. SEAI may inspect the work (random inspections)
5. The grant is paid (usually deducted from your final invoice)

Your contractor should be familiar with this process and guide you through it. If they seem unsure about SEAI requirements or paperwork, that’s a concern.

For more on grants, see our SEAI insulation grants guide. If you’re considering a whole-house approach, our One Stop Shop vs Individual Grants guide compares the two routes.

Frequently Asked Questions

How many quotes should I get?

Two or three is standard. More than three becomes time-consuming and the differences are usually small. Make sure all quotes are for the same scope of work so you’re comparing like for like.

Should I go with the cheapest quote?

Not automatically. The cheapest quote may use lower-quality materials, cover less area, or exclude items that others include. Compare the full scope, not just the price. That said, the most expensive quote isn’t automatically the best either.

What deposit should I pay?

A deposit of 10% to 20% is reasonable for larger jobs like external wall insulation. For cavity wall injection (a one-day job), no deposit should be needed. Never pay the full amount upfront. Payment on completion is ideal for small jobs.

Can I use a contractor who isn’t SEAI-registered?

You can, but you won’t qualify for SEAI grants. Given that grants can cover 50% to 100% of the cost for basic insulation measures, it rarely makes sense to go with an unregistered contractor.

What if I’m not happy with the work?

Raise it with the contractor first. Most issues can be resolved directly. If that fails, SEAI has a complaints process for work done under their grant scheme. This is another advantage of using an SEAI-registered contractor: there’s oversight and a route for complaints.

How far in advance should I book?

Insulation contractors can be busy, especially in spring and summer. For cavity wall injection, a few weeks’ notice is usually enough. For external wall insulation, book two to three months ahead during peak season (March to October).