Ask The Expert

Hi Sylvia,

Got a waterproof jkt reuqested to seam sealed. If laminated membrane MUST on the fab for applying sealed tape ? My understanding is mostly waterproof sealed tape is applied direct on laminated membrane. Got 2 fab w/knitted backing. One is 3 layer laminated (woven face+ membrane + S/J back)  , one is 2 layer bonded (woven face DWR5000mm + S/J back). Which is the option ? Can I apply sealed tape at kniited side ? If sealed tape affix secure on S/J knit ? Experienced only tricot , mesh backing on laminated fab could apply sealed tape ? If S/J & interlock can ? Thks ! 

Reply

If you try to heat seal tape on a conventional sewn seam with a knitted backing as descibed even if you get a bond, the fabric will act as a wick the water will pass along the threads and give you leakage outside the taped area. You may be OK if you use a welded seam process, but I would strongly recommend you test the composite seam for Waterproofness at a reputeable test house or invest in a Hyrostatic Head Tester. This type of equipment can be suppplied by SDL-ATLAS in the UK or China. Sylvia