Floor insulation

A good video on youtube about how to insulate a floor. 

Insulation a floor
( Poser un plancher isolant thermique)

Website to calculate how much 100mm flooring I need.


Shopping list

The price here comes in at about 50 euro/m sq = 3150 euro

Alternative cheaper product


This is Recticel FitForAll and here it’s sold in 30mm and 60mm sheets. But they are available up to 100mm (30mm, 40mm, 60mm, 82mm & 100mm) according to the Recticel Site 
Lambda 0.023

This would result in a cost of 945 Euros for 7m x 9m (15 euro TTC / m sq) 60mm sheets

From the following site, 100mm sheets are available for 28 euro / m sq (= 1764 euro for 7m x 9m)


GA4090 ( 1 304,52 € for 69.12m sq ) 90mm sheets 
Lambda 0.022 Watts per mK
R value  4.05


Wood Fiber General

Not too good really, 4cm
R value 1.05


Wood Fiber Pavaflex Confort

Conductivité thermique : 0,038 W/(mK)
100 mm : R = 2,60 m².K/W
180 mm : R = 4,70 m².K/W
200 mm : R = 5,25 m².K/W

180mm boards are 18.75 Euro/m sq = 1181 euro for 63 m sq

Video on installing floor insulation

Under screed (on slab) possability.

This EPS is much cheaper than more promoted branded stuff and probably just as good. Here is a company in POLAND

For example 64 sq metres of 20cm of this R6.45 (per 20cm) would be 817 euros.

Another good video on how to insulate the floor below. Has key details of where to put a vapour barrier – GRADE -> Gravel (with drainage) -> EPS foam -> Vapour barrier (also holds the foam down before 4″ of concrete is poured – > Concrete

Good video on insulation below slab from Kingspan


Thin sand blinding to level ->appropriate damp proof membrane (well lapped and folded), should lap high enough to connect with, or form, the wall damp proof course -> eps at least 2cm thick vertical around perimeter, top should be level with top of the floor screed (damp proof course), layer and overlap eps -> overlap eps boards with polythene sheet (as a vapour control layer), make sure polythene sheet has 150 mm overlap

PDF details 

Enterprise Etude Thermique

Researching companies that will carry out the Etude Thermique (Thermic Study) for our come and provide us with the certificate of conformity to RT2012 to add to our Permis de Construire document. 


  • Etudes thermique RT 2012 (Calcul du coefficient Bbio)
  • Attestation RT 2012 obligatoire pour votre permis de construire de construction neuve ou d’extension
  • Récapitulatif des minimas d’isolation à respecter

135 Euro


This is the one that An used and paid 199 Euros for. 

Pack Fin de travaux 199 €, includes:

Etude thermique RT 2012
Calcul du Bbio, du Cep et de la Tic
Délai de 7 heures ouvrées
Quelle que soit la surface
Etude certifiée
Décennale – RGE OPQIBI
Attestation du permis de construire
Dimensionnement des puissances de chauffage pièce par pièce et ECS
Modifications de votre étude
gratuites & illimitées
Conseils du thermicien
Par téléphone et messages
Calcul des énergies grises
Attestation de fin de travaux
remise des fichiers pour son édition