Expansion Joints and Pre-Compressed Sealants

Secondary sealant to directly applied, or typically applied, liquid sealants for joints in walls

Tech Data

Install Data


Guide Spec


Sample Request


en español

BACKERSEAL Installation Sequence Summary
(Direct-applied low-modulus silicone, binary-sealant installation shown).

BACKERSEAL is supplied in reels or for larger joints, in 'sticks'. It is precompressed to less than the joint size.

To open, the wrapper is cut next to the colored marker tape. The release liner is removed to expose a mounting adhesive on one face.

BACKERSEAL is unrolled, inserted into the wall joint and adhered to one of the joint faces.

With time the material expands firmly in the wall joint and adheres itself to the other substrate.

Joins between butt ends of lengths of BACKERSEAL.  A watertight join is achieved as the pressure-sensitive adhesive impregnation marries to itself at the join.

Low-modulus liquid sealant (Dow 790 silicone shown) is gunned into the joint over the BACKERSEAL. (Note: in conventional backer rod and liquid sealant installation, BACKERSEAL would be recessed to allow for installation of the appropriately-sized backer rod).

The liquid sealant is tooled firmly against the BACKERSEAL to complete the installation.

For use in walls and wall systems, BACKERSEAL is an economical, high-performance, secondary sealant to field-applied caulking featuring EMSEAL's exclusive, microcell-modified, acrylic impregnation technology. BACKERSEAL:

- provides R-value at joints;

- provides watertight  secondary seal;

- resists air pressure  differentials;

- remains firmly in compression against substrates;

- provides acoustic  dampening and;

- contributes to LEED.

Standard sizes: 1/4" (6mm) to 1 1/4" (30mm). Custom sizes 1/8" (3mm) to 6" (150mm).

Movement capability: +25%, -25% (50% total) of nominal material size.

Watertight, odorless, clean handling, UV stable, non-staining, low temperature flexible, high-temperature stable.

Unlike 'double caulk and backer rod', BACKERSEAL behind field-applied liquid sealants provides true "belt and suspenders" sealing--two systems working on different principles to perform the same function. 

'Double caulk and backer rod' is not only very difficult to install to achieve the geometry necessary to function in moving joints, but the same forces (primarily tensile stresses at the bondline and within the cured sealant) that will cause the outer installation to fail, will also likely cause the inner installation to fail as well.

By contrast, BACKERSEAL, because it works in compression, provides a practical to install, fully functional secondary seal using different performance principles than the primary, liquid sealant.  In addition it provides insulation and sound attenuation value as well as the ability to resist the effects of air-pressure differentials.

Ideally suited to panelized wall systems, curtain wall systems, as well as walls constructed of concrete, brick, stone, metal panels, etc.

Non-staining and compatible with wide range of liquid sealant and substrate materials.

Used as a secondary sealant behind:

1) Conventional backer-rod and liquid sealants

2) Behind directly-applied liquid sealant

Puncturing of liquid sealant facing does not affect sealant system performance.

Supplied pre-compressed to smaller than joint size with a mounting adhesive on one face. Material is inserted into joint and adhered to one side. It then expands to seal the joint.

Sealing between the foam and substrate is achieved through a combination of the pressure-sensitive adhesive impregnation and the active backpressure of the expanding foam.

*Sound Attenuation is also a feature of BACKERSEAL. With a 2 1/2" standard depth product installed in one side of a STC 68 wall, BACKERSEAL had a STC 53 rating and in an OITC 52 wall it had a 49 OITC rating. When installed from both sides of a STC 68 wall it received the maximum of STC 68 equaling the sound suppression of the wall and in an OITC 52 wall it received a OITC 51 rating.

STC 53 / OITC 49*

Empire State Building Uses BACKERSEAL around windows as part of $550 million energy efficiency retrofit: Joint sealants around the 6,500 refurbished windows are installed from swing stages on the Empire State Building.

EMSEAL JOINT SYSTEMS LTD. 25 Bridle Lane, Westborough, MA 01581
EMSEAL LLC. 120 Carrier Drive, Toronto, ON M9W 5R1



1-800-526-8365 -- 508-836-0280 --  techinfo@emseal.com -- Fax: 508-836-0281

Copyright © 1998-2015 by EMSEAL Joint Systems, Ltd. All rights reserved.
This document may not be reproduced in whole or in part without permission.