June 2018

Membranes
Step 3: Insulation
same depth, and more importantly to stop the fixings being
over or under tightened.
Mechanical attachment or adhering are the two
routes available.
To adhere SarnaTherm G insulation to an adhered vapour
barrier Sarnacol 2162 is poured from a 5kg tin into beads
SarnaTherm G PIR insulation boards can be
which should be 10mm-20mm in width, alternatively the
installed by either method. When a polyethylene
VCL is installed, the insulation boards are then Step 3: SarnaTherm G insulation adhered to the air Sika C-250 spray applied insulation adhesive can be used
vapour barrier using Sika C-250 spray applied to speed up the installation.
loose laid and mechanically fixed by means of insulation adhesive.
Sarnafil fixings, insulation pressure plates and
The distance between each bead is in the Sarnafil
thermally broken tube fasteners. Using the nylon tubes - which prevent cold specification depending on the wind uplift calculations. After an hour the
bridging - means that the insulation boards can be kept as thin as possible adhesive should have cured enough to stop the board lifting but we advise
thus reducing the cost of the insulation.
that the boards are trafficked as little as possible.
The tubes are installed using a TP 19 fixing tool. This tooling acts as a
depth gauge or torque adjuster to ensure all fasteners are installed to the
If a board is tilted on an uneven deck, once it comes out of the semi cured
adhesive it will not adhere back in and so should be taken up and re-stuck.
Step 4: SarnaTherm HD
The Sarnafil HD system is made even tougher by
installing a high density PIR insulation board
underneath the Sarnafil membrane. This
SarnaTherm HD insulation can withstand impact and
high weight loadings. The boards should be adhered
to the surface of the preceding SarnaTherm G
The SarnaTherm HD boards are adhered to the
surface of the preceding SarnaTherm G insulation
using the C-250 insulation board adhesive.
insulation, bonded board to board by means of Sarnacol
2162 or adhered using the C-250 spray applied
insulation board adhesive.
If mechanically fixing the HD insulation, the first layer of
SarnaTherm G should be pinned into position and then
the fixation of the SarnaTherm HD carried out to the
Sarnafil specified fixing pattern and fastener density.
Step 5: Sarnafil HD Membrane
spray tip nozzle clean. If and when work is interrupted,
immerse the spray tip in cleaner and spray the end of
Now for the membrane itself. The installation of the
the applicator gun with a solvent flushing spray to
2mm thick G410-20EL Sarnafil HD membrane to the
remove excessive adhesive that could cure and block it.
SarnaTherm HD insulation is by method of adhering
the membrane using either Sarnacol 2170 roller
By keeping the canister turned fully on and controlling
applied contact adhesive, or by using the new Installation of the 2mm thick G410-20EL Sarnafil HD the adhesive by the control on the applicator gun,
membrane to the SarnaTherm HD insulation boards
Sarnacol 2172 spray applied contact adhesive. The using Sarnacol 2170 roller applied contact adhesive. pressure is kept throughout the hose and gun which will
spray applied version delivers quicker installation
keep the adhesive from curing inside it.
times, less stress on the applicator and less waste of product.
The application is a thin covering as a primer coat and then another
Sarnacol 2172 comes in an 18kg canister to which a hose and applicator adhering coat to the back of the membrane. The two are put together and
gun is connected. At the end of the applicator gun a small spray tip nozzle rolled over with a water filler roller to expel air bubbles and wrinkles and
is screwed on. This makes the adhesive spray out in what is called a ‘spray achieve an intimate contact. Finally, to seal the overlaps seams should be
fan’, which is a more controllable pattern than just delivering it like an heat welded either by a Sarnamatic automatic welding machine or hand
aerosol spray. The important factor for the spray products is to keep the welded using a Leister triac hot air gun.
“Attention to detail and following these
procedures will deliver a roof to be proud of and
one that withstands the pressures of modern
construction methods”
Contact Sika Sarnafil
01707 394444
gbr.sarnafil.sika.com
@SikaSarnafilUK
44 TC JUNE 2018