(02) 8021 3517 Send your job →
● On site

Movement joint waterproofing. How a joint is sealed.

1 min readFORSPEC Technical Team

The short version

  • A perimeter movement joint sealed with EXPANDOFLEX FT tape.
  • The tape has felt on both edges and a plain centre. The membrane bonds into the felt; the centre is left free to move.
  • The edges are bedded in PROBOND 1100 epoxy and left for 24 to 48 hours before the membrane.
FORSPEC drawing of a movement joint: joint tape bonded at its edges in epoxy, centre left free, membrane lapped onto each edge
The tape bonded at its edges and free in the middle.

A building moves at its joints. A membrane painted straight across a joint is stretched every time it does, and sooner or later it tears.

How the tape is fixed

  1. Trowel PROBOND 1100 epoxy 1.0 to 1.5 mm thick on each side of the joint.
  2. Press only the underside of each edge into the wet epoxy. Keep epoxy off the felt and off the centre.
  3. Cap the edges with epoxy, 20 mm past the tape, and leave for 24 to 48 hours.
  4. Apply the membrane onto the felt, at least 100 mm past each edge. Never coat the centre.
FORSPEC on Instagram · 21 Oct 2026A perimeter movement joint in EXPANDOFLEX FTLoads when you tap

Where this comes from

Standards are summarised in FORSPEC's own words as a guide. Read the standard itself and your project documents before you build.

Email thisNewsletter

Systems, products and drawings

SystemBalcony & Podium Waterproofing (Under Tile or Screed)The full build-up, layer by layerSystemBelow-Ground Waterproofing & Basement TankingThe full build-up, layer by layerProductEXPANDOFLEX FT JOINT TAPEFelt-laminated TPE expansion joint tape that lets liquid and sheet membranes terminate into it seamlessly.ProductPROBOND 1100Two-component structural epoxy paste for crack repair, bonding new to hardened concrete, anchoring and void filling.RangeAll FORSPEC productsBy system, with data sheets and calculators
● Your job next

Got a job this applies to?

Send the drawings or a few photos. FORSPEC comes back with the system, the details and the products for your job, within 6 business hours.

Send us your job →Call (02) 8021 3517

On site with FORSPEC

A lift pit lined before the pour, from FORSPEC on InstagramA lift pit lined before the pourThe membrane under the screed, from FORSPEC on InstagramThe membrane under the screedA pool detailed the right way, from FORSPEC on InstagramA pool detailed the right wayPipe details welded into the sheet, from FORSPEC on Instagram▶ 3.2KPipe details welded into the sheet
@forspec.pc on Instagram →

More news

Two concrete tanks wrapped in blue ACTFLEX 5000 self-adhesive sheet membrane, starter bars above the walls and a crane behindTwo concrete tanks wrapped in ACTFLEX 5000On site1 min readLift pit lined in grey PREFLEX 3000 pre-applied sheet membrane, with sealed pile heads and starter bars standing up through the sheetA lift pit lined with PREFLEX 3000 before the pourOn site1 min readFORSPEC drawing of a bathroom floor with the sheet membrane under the screed and the wall membrane brought down over the sheetThe membrane under the screed, on every floorOn site1 min read
All news →
● The FORSPEC Brief · monthly

The month in waterproofing. In one email.

Code and standards changes, new products, new test reports and jobs from site. Once a month. No sales emails.

One email a month. Unsubscribe in one click. We never share your address.

Send us your job →☎