KORE vs ISOQUICK
Two EPS insulated foundation systems, compared using each supplier's own certificates and published figures.
Who wrote this: ISOQUICK, so we have a stake in the answer. To keep it fair, every KORE statement below comes from KORE's own product page or its BBA certificate, and every ISOQUICK statement comes from our Kiwa certificate, our published U-value tables or is marked as ISOQUICK's own position. We have not tested either product. Check current details with each supplier. Part of a wider comparison of UK insulated foundation systems.
At a glance
| KORE Insulated Foundation | ISOQUICK | |
|---|---|---|
| Insulation | EPS 100, 200 and 300 (white). Its BBA certificate covers EPS 100 (λD 0.036) and EPS 300 (λD 0.033). | EPS in three grades: IQ-60e (200 kPa, λD 0.031), IQ-90 (300 kPa, λD 0.033) and IQ-210 (700 kPa, λD 0.034), per the Kiwa certificate. |
| Design | KORE's page says the system "works much like a traditional raft". Its BBA certificate describes EPS 300 profiles forming the perimeter, cut out to form an outer ring beam, with concrete for "outer ring beams and internal beams". | ISOQUICK describes its system as a flat raft, where wall loads are spread across the slab rather than concentrated in a perimeter beam. |
| Certification | BBA Agrément Certificate 24/7229, Product Sheet 1 (issued 21 November 2024). NSAI certificate 20/0424 stated on its page. | Kiwa BDA Agrément BAF-20-179-S-A-UK, for new dwellings (first issued February 2022, reissued July 2025). Also a Certified Passive House Institute component (certificate 0379fs03) for ICF, external-insulation and lightweight-timber connection details. |
| Published U-value | "As low as 0.10 W/m²K"; typical 0.10–0.11. Chart: 0.076–0.105 across P/A 0.10–0.60. BBA examples: 0.08–0.10 (general floor) and 0.10–0.12 (perimeter application). | 0.07–0.18 W/m²K across grades, depending on under-slab insulation (150–300 mm) and P/A ratio. For example, IQ-60e with 200 mm under-slab insulation gives 0.09 at P/A 0.1 rising to 0.13 at P/A 0.6 and above; with 300 mm, 0.07 rising to 0.09. |
| Published Psi-value | None on its page. The BBA certificate lists only the generic SAP default for a ground-floor junction (0.32 W/mK), which is not a KORE-specific figure. | ISOQUICK states a PHPP Psi-value below 0.1 W/mK for a typical 200 mm build-up. The Passive House certification criterion for certified details is Ψe ≤ 0.01 W/mK. |
| Concrete | BBA minimum C28/35. Example U-values assume a 150 mm slab (general floor) and a 250 mm slab (perimeter). Its page states both "up to 40%" and "50 and 60 percent" less concrete than traditional foundations. | U-value tables assume a 250 mm slab with 100 mm below ground level. ISOQUICK's standard specification is a minimum of 200 mm of concrete. |
| Supply | Manufacturer based in Cavan, Ireland; approved installer directory. Offers itemised cost comparisons against strip and raft foundations on request. | Design support and supply. |
Sources: KORE product page and BBA certificate 24/7229; ISOQUICK Kiwa certificate BAF-20-179-S-A-UK, U-value tables TD-0002 and TD-0004 (May 2025) and Passive House Institute certificate 0379fs03.
The main design difference: ring beam or flat raft
Both systems wrap a concrete slab in EPS. The difference is in how the slab is built. KORE's certificate describes an EPS 300 perimeter profile that forms a ring beam, with insulation layers inside it. ISOQUICK's position is that a flat raft, which keeps the slab a consistent thickness and spreads wall loads across it, gives a simpler reinforcement design and keeps the insulation under the slab edge uniform.
This is a design argument, not a settled fact, and it has been debated in the trade press. In a 2019 Passive House Plus guide, KORE's technical sales manager said that its standard form is an insulated foundation system that takes elements of both raft and strip designs, and that it can be designed as a raft where ground conditions require. The same guide reported ISOQUICK's view that a ring-beam design concentrates load on a narrow strip of insulation. Both are supplier positions. What matters for your project is what the engineer designs for your ground and walls.
ISOQUICK explains its reasoning in What is the difference between an insulated foundation and an insulated raft?
Certification: what each certificate covers
Both suppliers hold a UK building-product approval (BBA for KORE, Kiwa BDA Agrément for ISOQUICK). Each assesses that the system is fit for its intended use when installed as specified. They are separate schemes, and neither is a ranking of the products against each other.
ISOQUICK also holds a Passive House Institute component certificate, which sets a thermal-bridge criterion (Ψe ≤ 0.01 W/mK) for the connection details it certifies. Those details are ICF, external insulation and lightweight timber construction. KORE's page does not cite a Passive House Institute certificate. Ask either supplier which connection details and wall types their certificate covers.
Comparing the U-values fairly
The figures in the table are not like-for-like. KORE's BBA examples use a 150 mm slab over 300 mm of EPS 100 for the general floor, and a 250 mm slab over 200 mm of EPS 300 at the perimeter. ISOQUICK's tables assume a 250 mm slab and vary the under-slab insulation from 150 to 300 mm. Neither set of numbers can be read across to the other without the same build-up and P/A ratio. Ask both suppliers for a calculation for your own building.
Concrete and cost claims
KORE states 13% and 16% savings against strip and raft foundations for a pair of semi-detached houses and offers an itemised report on request. This page does not compare price. Whichever supplier you speak to, ask for the itemised basis, including groundworks, concrete, reinforcement, labour and programme, and check it against your own site.
Questions to ask both suppliers
- What is the U-value for my P/A ratio, and what slab thickness and insulation depth does it assume?
- What is the Psi-value at the wall-floor junction for my wall type, how was it calculated, and by whom?
- Is the slab a flat raft or does it have ring beams, and why is that right for my ground?
- Does the certificate cover my wall type, and when does it expire?
- Who designs the slab, who takes responsibility for it, and what does the engineer need from me?
Get ISOQUICK figures for your project
Send us your plans and wall type and we will give you the U-value, the junction detail and the certification that applies.
Get a Quote All systems comparedSources
- KORE Insulation — KORE Insulated Foundation System; BBA Agrément Certificate 24/7229 Product Sheet 1, issued 21 November 2024
- ISOQUICK — Kiwa BDA Agrément BAF-20-179-S-A-UK; U-value tables TD-0002 and TD-0004; Passive House Institute certificate 0379fs03
- Passive House Plus — The PH+ guide to insulating foundations (June 2019)
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