Component S
Component S is the usual choice for roof cavity filling where load-bearing and exposure are not issues. Where the foam is the visible surface, use A.
See specificationRoofs
Roof insulation and repair without removing the deck
A metal roof leaks at a fastener and condenses everywhere. Foam fixes the leak and the condensation in the same visit — from underneath, without a scaffold.
What goes wrong on site
Three failures, in the order they appear
- 01
Retrofit: the deck cannot come off, the tenant cannot move out.
- 02
Condensation on the underside of metal, dripping onto stock.
- 03
Leak points are hard to find: water travels along the purlin before it drips.
Why one-component foam, and not something else
Three properties, no chemistry
- Mobility: a can and a gun reach a joint that a panel, a board or a truck cannot.
- Irregular geometry: it expands to the shape of the void, including penetrations.
- Closed cell: air barrier and moisture barrier in one pass, without a second trade.
How it is done, and what to hold
The four numbers this job lives on
| Step | What to hold |
|---|---|
| Surface | Dust and loose rust removed, fastener heads checked, water stopped before foam goes on. |
| Fill volume | One third of the joint depth. The foam expands to fill; filling it to the top bends frames and wastes material. |
| Passes | Two passes of 30 mm at most. A single thick pass traps heat and collapses in the core. |
| Trim | Cut after the window on the parameter card. Never pull or press uncured foam. |
| Cover | PU is not UV-stable. Any exposed face gets sealant, render or a trim within 48 hours. |
Typical guidance. The parameter card for your grade carries the tolerances your operators work to.
Common failures
Three ways this job goes wrong
- Foaming over an active leak: the water finds the next seam.
- A thin coat that closes the surface but leaves the cavity open to air movement.
- Walking on uncured foam, or trimming it while it is still tacky.
What to tell your customer
Three sentences you can copy into a quotation, a WhatsApp message or a site meeting. Your competitors' websites talk about themselves; this block is for you to talk about the job.
„We treat the leak and the condensation in one visit, from inside.“
„No deck removal, no scaffold, no tenant disruption.“
„Fastener heads and seams are sealed first — the foam is not the waterproofing.“
Send the drawing or the photo — we will reply with the parameters.
Technology brand
Tell us the joint, the substrate and the season
- 1 tonne minimum, five 200 L drums
- SDS, COA and Form E with every shipment
- We reply within 24 hours, Monday to Saturday.