In general, the total rabbet depth for each profile should include a minimum of 3/4
inch sheet engagement and an allowance for thermal expansion. Due to the rib
geometry of 16 mm and thicker Multiwall sheet, additional precautions should be taken. In
this case it is important that the sheet is cut so that as
least one rib is located in the center of the rabbet, as shown in Figure 33.
Dry Glazing Systems
This selection illustrates some glazing proposals, illustrating
profiles which have been successfully used in combination with multiwall
sheet. Situations may occur where sheet expansion ( sheet dimension
greater than 4'x 4')exceeds sealant limitations
and often for aesthetic reasons, this type of "dry" glazing
system is an ideal solution.
The advantage and necessity for dry systems is that the rubber gaskets
are 'snapped' into the glazing strips which then allow free movement of
the sheet during expansion and contraction. See fig. 34 and 35.
Do not use PVC gaskets!
Due to migration of additives (Plasticizers) from soft
Polycarbonate can be chemically affected resulting in surface cracks
or even sheet breakage.
MJK Multiwall Systems, LLC offers range of easy to use glazing bars and fixing accessories,
designed specifically for glazing Multiwall & monolithic polycarbonate
and acrylic sheet.
Wet Glazing Systems
This type of installation system is mainly used in small (leas than
applications: car ports, warehouses, conservatories and other glass replacement
With standard metal profiles or wooden sections, in combination
with glazing tapes and glazing compounds, many different configurations
are possible. See fig. 36 and 37.
When using glazing compounds it is essential that the sealant
system accepts a certain amount of movement, to allow for thermal expansion,
without loss of adhesion to the frame or sheet. Silicone sealants (100%
generally recommended for use with Polycarbonate sheet, but it is
strongly advised when using sealing compounds to check compatibility before
Care should be taken not to use amino or benzamide curing
silicone sealants, which are not compatible with Polycarbonate sheet and result
in micro-cracks particularly when stress is involved. See
fig. 22 for sealant recommendations.
©2005 MJK Multiwall Systems, LLC