Replies

1. 
   user-2310254 | Feb 14, 2021 03:27pm | #1

   Mike,

   Here's a quote from Martin's backyard tape test: "This test taught me that XPS is one of the hardest substrates to tape; it’s even harder to tape than OSB. The best of the tested tapes on XPS was Siga Sicrall."

   That said, I'm not sure how important it is to tape the seam. After all, you should be placing a layer of poly over the entire thing. That will be your air barrier.

   But let's see if an expert will add to the conversation.

2. Expert Member
   Michael Maines | Feb 14, 2021 04:33pm | #2

   3M 8067 All-Weather Flashing Tape is available at lumberyards around here, is affordable and sticks well to most things, even if they're wet. I believe it would hold long enough but if you're concerned you could upgrade to one of the Siga tapes that Martin recommends here: https://www.greenbuildingadvisor.com/article/return-to-the-backyard-tape-test.

3. Expert Member
   Akos | Feb 14, 2021 04:46pm | #3

   Up here we have Tuctape, commonly used for vapor barriers. Cheap and sticks well.

   Since it is temporary, you can probably go with anything inexpensive, even ductape or heavier duty packing tape.

1. 
   charlie_sullivan | Feb 14, 2021 07:24pm | #6

   There's a Gorilla brand heavy duty packing tape that would be a cheap temporary make-do option. 3M 8067 would be my choice if you want something stronger.

4. 
   ohioandy | Feb 14, 2021 05:16pm | #4

   So wait, you're wanting to tape the XPS sheets together so they don't blow away while you're waiting a few weeks until the pour actually happens? Not sure what's spec'ed for reinforcement, but as Steve says, you'll of course have 6-mil poly on top, followed maybe by mesh or rebar, so that and a few cinder blocks should hold things down. An additional worry is the frigid cold weather that a lot of CZ 4 is seeing this month--is there any thought to laying blankets to keep the prepared substrate from wetting/freezing/heaving before the pour?

1. 
   mikeysp | Feb 14, 2021 07:01pm | #5

   Andy, I am not worried about it holding down, but the 4ft x 26ft sheets of 1" x 2 layers, shifting around at all. I think any simple tape like tyvek or packing tape will probably work. It only needs to hold it a little untill the prep is done and maybe 1-3 weeks as we wait on the concrete crew.

   -Mike

5. 
   Mark_Nagel | Feb 14, 2021 08:30pm | #7

   I've seen it being a requirement(?) by manufacturers of some products that the sheets are staked into the ground. I think Warm Form does/requires this, in which case you might find a pointer there.