Is Knauf insulation safe to install yourself?

Loft Roll 44 is DIY-friendly if you wear a mask, long sleeves, and gloves. Cavity and solid wall products aren't.

Does Knauf insulation contain harmful chemicals?

Knauf's UK mineral wool is bio-soluble, meaning any fibres that get into your lungs break down within a few weeks. It's classified as non-hazardous by the EU and the World Health Organization removed mineral wool from its cancer risk list back in 2001. You'll still itch if you handle it without gloves, and you should wear a mask when cutting or installing, but the old asbestos-era concerns don't apply to modern mineral wool.

How long does Knauf loft insulation last?

Between 40 and 50 years if kept dry and undisturbed. The main killer is water damage from roof leaks or condensation, which mats the fibres down and destroys the thermal performance. If you've had a leak, replace the affected section rather than trying to dry it out.

Can I install Knauf cavity wall insulation in an older home?

Only if your home has an actual cavity, which usually means built after 1920. Older solid-wall homes need internal or external insulation instead.

What's the difference between Knauf Loft Roll 44 and Loft Roll 40?

Loft Roll 40 has better thermal performance (0.040 W/mK vs 0.044 W/mK), meaning you need slightly less thickness to hit the same U-value. In practice the difference is marginal for a standard loft top-up, and Loft Roll 44 is what most installers stock. If you're doing a room-in-roof conversion where thickness is constrained, the 40 version is worth the extra cost. For a normal joisted loft with 270mm of headroom, don't bother.

Will Knauf insulation improve my EPC rating?

Yes, and often by a full band. Going from an empty loft to 270mm of Knauf Loft Roll typically moves a home from EPC E to D, sometimes E to C if other measures are already in place.

Knauf Insulation 2026: Is It Right for Your Home?

Knauf Insulation 2026: Is It Right for Your Home? | Eco Home Check

What Is Knauf Insulation and What Products Do They Make?

Knauf is a German manufacturer that makes about a third of the mineral wool insulation sold in the UK. Their factory in St Helens has been producing glass and rock wool for over 30 years, and most MCS-registered installers we speak to use their products by default.

The range is broad. You've got loft rolls, cavity wall batts, external wall insulation boards, floor slabs, and acoustic products for internal walls. Each is designed for a specific job, and using the wrong product in the wrong place is a common installer mistake.

Here's what they actually make, in the order you're most likely to encounter them:

Loft Roll 44. The yellow-ish glass wool you see rolled out between joists. Thermal conductivity of 0.044 W/mK, which is decent but not the best on the market.
Dritherm Cavity Slab 32 and 37. Rock wool batts pushed into wall cavities during construction or retrofitted through drilled holes.
Rocksilk RainScreen. A stiffer rock wool board used behind external cladding on solid walls.
Earthwool Frametherm. Slabs for timber-frame internal walls, popular in new-build.
Space Blanket. A pre-cut loft product that goes down faster than standard roll, mainly used by professional installers.

Beyond those, the catalogue runs to hundreds of SKUs including pipe insulation, acoustic slabs, and specialist products for commercial roofs. Most homeowners will only ever encounter three or four of them.

One thing worth flagging. Knauf's mineral wool is not the same as PIR foam boards (Celotex, Kingspan). Mineral wool is fluffier, cheaper per square metre, and better at soundproofing. PIR is thinner, more expensive, and gives you a lower U-value in a slimmer wall. Different products, different jobs.

Which Knauf Insulation Product Suits Your Home Best?

It depends on where you're insulating and what's already there. Loft, cavity wall, and solid wall each need a different product, and getting the match right matters more than the brand.

Start with your loft. If it's empty or has less than 100mm of old insulation, you want Loft Roll 44 laid to 270mm total depth. That's the current building regs recommendation and it's what ECO4 installers fit as standard. Anything less and you're leaving heat on the table. Anything more and you're into diminishing returns.

Cavity walls are more finicky. If your home was built between about 1930 and 1995 and has an unfilled cavity, Dritherm 32 or 37 is what most installers use. The 32 is denser, higher performance, slightly more expensive. The 37 is the workhorse and covers the vast majority of retrofit jobs.

Solid walls are the hardest case. Homes built before 1930 typically have solid brick or stone walls with no cavity to fill. Here you're looking at external wall insulation (Rocksilk RainScreen behind render or cladding) or internal wall insulation (Earthwool slabs on a stud frame). Both are expensive. Both change how your walls look. We've covered the full picture in our room in roof insulation guide, which touches on solid wall options for older properties.

A quick note on soundproofing. If your issue is a noisy neighbour rather than heat loss, Knauf's acoustic range (Earthwool Acoustic Roll) is a completely different product from the thermal versions. Same fluffy stuff, but denser and tuned for sound rather than heat.

How Much Does Knauf Insulation Cost to Install in 2026?

A typical UK loft top-up costs £400 to £700 fitted, with the Knauf material itself coming to around £150 to £250 of that. Labour is the bigger line.

But the range is wide, and the type of insulation you need swings the cost dramatically. Here's what we see in real quotes across the UK in 2026:

Product	Material cost per m²	Typical fitted cost (whole job)
Loft Roll 44 (200mm top-up)	£5 to £8	£400 to £700
Loft Roll 44 (full 270mm fresh install)	£8 to £12	£700 to £1,200
Dritherm Cavity Slab (3-bed semi)	£10 to £15	£700 to £1,500
Rocksilk RainScreen (external wall, whole house)	£20 to £30	£8,000 to £15,000
Earthwool Frametherm (internal wall)	£8 to £14	£5,000 to £10,000

Material prices from Knauf have risen roughly 12% since 2022, tracking energy costs and gas prices used in manufacturing. Fitted costs have risen faster because installer day rates have gone up more sharply than materials.

One thing that catches people out. The building materials merchants price Knauf differently to the trade. If you're planning to DIY a loft top-up, expect to pay retail rates at Wickes or B&Q (about £8 per square metre for Loft Roll 44). Trade counters like Jewson knock 20 to 30% off, but you usually need an account.

And here's the honest bit. Knauf isn't the cheapest brand. Isover (owned by Saint-Gobain) and Superglass are usually 5 to 15% cheaper for equivalent products, and thermal performance is nearly identical. What you're paying for with Knauf is availability, installer familiarity, and a longer warranty on some product lines. Whether that's worth it depends on how much you care about brand consistency.

Can You Get a Grant to Cover Knauf Insulation Costs?

Yes, ECO4 and the Warm Homes: Local Grant can both cover Knauf insulation in full for eligible households.

ECO4 is the main route. It's funded by energy suppliers, runs until December 2026 in its current form, and pays for the full install if you meet the criteria. Those criteria centre on benefits (Universal Credit, Pension Credit, income-related ESA, and others) plus a home EPC rating of D, E, F, or G. About a third of UK households qualify, though many don't realise it.

We've written the full ECO4 eligibility rules separately, but the key thing for insulation specifically is that ECO4 covers loft, cavity, and solid wall through the same application. The installer submits a whole-home assessment, and if insulation is the cheapest way to improve your EPC, that's what gets funded.

Warm Homes: Local Grant is the newer route, administered by local authorities. Funding varies by council. Cornwall, Nottingham, and Greater Manchester have been generous. Some southern councils have barely touched it. The scheme runs until March 2028 and eligibility is broader than ECO4 in some areas, so it's worth checking even if you've been turned down for ECO4 before.

A quick note on GBIS. The Great British Insulation Scheme closed in March 2026. If you see installers still advertising "GBIS-funded insulation", that's either old marketing or they're actually referring to ECO4. Ask which specific scheme they're claiming under.

Our insulation grants guide covers the full picture including pensioner-specific routes and how to combine schemes with other measures like boilers or heat pumps. If you're a pensioner specifically, the pensioner insulation grants page covers Pension Credit routes and how ECO4 Flex works when you don't get the qualifying benefits directly.

The Boiler Upgrade Scheme doesn't fund insulation, but it does interact. If you're planning a heat pump install, most installers now insist on decent insulation first (typically EPC C or better), so the two often go together.

Worth checking your eligibility before you commit to anything. The eligibility checker runs through ECO4 and Warm Homes: Local Grant in about two minutes.

Knauf vs Other Insulation Brands: How Does It Compare?

Knauf sits in the middle of the market on price and near the top on availability. Isover is cheaper for equivalent thermal performance. Kingspan and Celotex are better if you need thinner walls.

Here's how the main brands stack up for the products most homeowners actually buy:

Brand	Best for	Thermal conductivity	Price vs Knauf
Knauf	Loft, cavity, external wall	0.032 to 0.044 W/mK	Baseline
Isover	Same as Knauf	0.032 to 0.044 W/mK	5 to 15% cheaper
Superglass	Loft roll	0.040 to 0.044 W/mK	10 to 20% cheaper
Rockwool	Cavity, acoustic	0.034 to 0.037 W/mK	Similar to Knauf
Kingspan (PIR)	Solid wall, floors, roofs	0.022 W/mK	2 to 3x more expensive per m²
Celotex (PIR)	Solid wall, floors, roofs	0.022 W/mK	Similar to Kingspan

For a standard loft top-up, brand basically doesn't matter. Loft Roll 44 from Knauf and Isover 44 do the same job to within a percent or two on thermal performance. Buy whichever is cheaper at your local merchant.

For cavity walls, we'd actually lean slightly towards Rockwool Cavity Batts over Knauf Dritherm for one reason. Rockwool holds its shape better if the cavity has any moisture issues, which matters more than the tiny thermal difference. Both are fine products.

For solid wall insulation where wall thickness matters, mineral wool (Knauf, Isover, Rockwool) is the wrong product. You need PIR (Kingspan, Celotex) to get the required U-value in a reasonable thickness. This is where Knauf loses out entirely. They don't make PIR.

Here's what most guides won't tell you. The brand debate matters less than the installer. A brilliant installer with a mid-tier product will beat a mediocre installer with premium materials every time. When we look at heat loss surveys after retrofit, the failures are almost always installation gaps (missed corners, compressed material, cold bridges), not the material choice.

So. Get the installer right first. The brand comes second.

How to Find an Installer and Get Started Today

Start with grant eligibility, then work backwards from there. If you qualify for ECO4 or Warm Homes: Local Grant, the scheme picks the installer. If you're paying yourself, you have more choice and should get three quotes.

For grant-funded work, the process is roughly this. You apply through an installer who's registered under the scheme, they carry out a home assessment (usually free), and if you qualify they book the install. You don't choose the brand of insulation. The installer uses whatever their supply chain offers, which in most cases is Knauf, Isover, or Superglass depending on region.

For self-funded work, get three quotes from installers listed on the TrustMark register. TrustMark is the government-endorsed quality scheme for retrofit work, and any installer doing loft or cavity insulation should be signed up. Ask specifically which product they'll use and what thickness they're quoting.

One mistake to avoid. Don't accept a cavity wall install without a borescope inspection first. A good installer will drill a small hole, check the cavity condition, and confirm it's clean and dry before quoting. If they skip this step, walk away. We've seen too many failed installs where the cavity was never suitable in the first place. Our cavity wall insulation removal guide covers what happens when it goes wrong.

To check what grants you're entitled to before contacting installers, the eligibility checker takes about two minutes and covers every current scheme.

One last thought. If your home is EPC D or worse and you're on any means-tested benefit, don't pay for insulation yourself before checking ECO4. We regularly see people who've spent £2,000 on a loft top-up they'd have got free. The application process is a bit annoying but the money involved is real.