Assembly Instructions
© 12/14 Allura, Printed in U.S.A.
www.AlluraUSA.com
Allura USA | 15055 Woodham Drive | Houston, Texas 77073 | 1 844 4 ALLURA (1-844-425-5872)
© 12/14 Allura, Printed in U.S.A.
Installing caulking at ber cement siding
bu joints/edges during installaon
Bu end/joints should be installed with factory-sealed
or factory-prenished ends bued together in moderate
contact. 2006 Internaonal Building Code: 1405.17.2
Horizontal Lap Siding states the following regarding applying
caulk at the bu end/joint of horizontal lap siding:
Lap siding shall be lapped a minimum of 11/4 inches
(32 mm) and shall have the ends sealed with caulking,
covered with an H-secon joint cover or located over a
strip of ashing. Lap siding courses shall be permied to
be installed with the fastener heads exposed or concealed,
according to approved manufacturers’ instrucons.
The goal of the methods outlined both by Allura and
the Internaonal Building Code for installing the bu
end/joint of ber cement siding is to manage the ow
of water at these areas. Requiring the installer to “back
ash” the bu the end/joint of two panels in moderate
contact increases the aesthec appearance of the nished
bu end/joint while eliminang any requirements for
future maintenance of the caulking at the bu end/
joint. Applying caulk to the bu joint can be ineecve
due to the gap not being large enough to accommodate
the sealant, and on prenished products it may leave an
unsightly looking nish. Spreading or feathering the sealant
into a thin lm will create a noceably dierent appearance,
and can also remove the needed thickness required to
withstand UV exposure and joint movement. In place of
caulk Allura recommends (but does not require) the use of
a bu end/joint ashing made of a durable, non-corrosive
material that is compable with ber cement siding (e.g.
15 lb felt, trim coil, joint ashing, etc). Addionally, many
sealant manufacturers have changed their installaon
instrucons to disallow gapping the siding and applying
caulk at the bu end/joint during installaon (although
some sealant manufacturers do sll allow for back-buering
(Caulk) the edges of the panel at the bu end/joint).
NOTE: Refer to your sealant manufacturer’s specicaons
to determine if they allow the caulking of ber cement
siding bu joints/edges, what their minimum and maximum
gap requirements are and/or how this pracce may aect
the warranty for the caulking.
If the architect, designer, installer, project manager,
contractor, property owner, code ocial or other enty
involved with determining the method of installaon on a
project determines that spacing the bu joints and applying
caulk is an acceptable pracce during installaon, such
pracce will not aect the eligibility of the Allura Fiber
Cement Siding product installed on the project for warranty
coverage with regards to product defect, provided that the
caulking of the bu joints does not inict, cause, or otherwise
create a condion where this pracce was, is or becomes the
cause of product failure.
(Connued on reverse side)
TECHNICAL BULLETIN
Applying Caulking at Allura Fiber
Cement Siding Bu Joints