Knowledge Bank › Install › Installation Guide
How to Install an Expansion Joint Cover
A correctly installed expansion joint performs for decades; a poorly installed one leaks, rattles or fails early. This is the general sequence for a surface- or recess-mounted building joint cover — always follow the product’s own method statement.
Before you start
- Confirm the joint gap on site matches the ordered system’s range.
- Check the substrate is sound, level and cured.
- Have the correct fixings, primer, adhesive/sealant and end/corner accessories.
Installation sequence
1. Prepare the joint edges. Clean out debris and laitance; form a true, straight, sound edge. For recess-mounted floor systems, verify the block-out depth and width.
2. Dry-fit & set out. Position the frames/base rails along the joint, align across the gap, and mark fixing points. Set the centre plate or seal to its nominal (mid) position.
3. Prime & bed. Prime the substrate where required and apply the bedding adhesive/sealant per the datasheet.
4. Anchor the frames. Fix the base frames with the specified stainless anchors at the stated spacing. Do not over- or under-tighten.
5. Install the seal / cover. Fit the EPDM gland or cover plate; on deck systems, weld or bond the membrane flashings to achieve the watertight seal.
6. Terminate ends & corners. Install end caps, transitions and corner units; seal all interfaces so the run is continuous.
7. Check & clean. Confirm the cover sits flush and centred, moves freely, and (for watertight systems) passes the specified water test. Clean off surplus sealant.
⚠️ Common mistakes: setting the joint off-centre (loses movement range), skipping the primer (seal debonds), over-tightening anchors, and not sealing end/corner transitions (the usual leak point).
Frequently asked questions
Should the joint be set open or closed at install?
Set it to its nominal mid position so it has full range to both open and close — unless the datasheet specifies a pre-set based on the temperature at installation.
How is a watertight deck joint sealed?
Its membrane flashings are welded or bonded to the deck waterproofing so the joint is continuous, then water-tested. The gland provides the primary seal.
General guidance only — always follow the specific product method statement. Dseal provides installation support on request.