Tile Backer Board

Archive of Older Topics Archive - Product Discussions #4
1

Is anyone familiar with, or has used a tile backer board called “WEDI BOARD?”

It is proposed as a substitution on a large federal project that we specified and consists of a polystyrene core and fiberglass mesh and polymer-modified mortar faces. The manufacturer claims it can be used on walls and floors…

2

It appears to be a foam plastic material. Their product data indicates:

“Coverings that provide a 15-minute thermal barrier, such as ceramic tile, are regarded as acceptable in most applications.”

I would have the contractor first get it approved by the local jurisdiction to be acceptable in accordance with Section 2603 of the IBC.

3

Full disclosure Wedi is a competitor of mine
Wedi is very similar to the Schluter Kerdi Board, a light weight board used mostly in shower applications (they are waterproof, though you still have to address the seams and penetrations). These types of backerboards are typically much more expensive then Cement Backer Boards (CBU). If it is a large format tile or stone then check with Wedi for limitations on weight and size of tile or stone.
Advantage, lightweight, easier and quicker to install. Coating of board is waterproof.
Foam backer boards like Wedi do not have an ASTM standard. There are standards for the foam, but not for the composite board or applications in installing tile. Wedi does have an ICC-ES report for waterproof panel. Wedi type boards do have approval by TCNA for one type of wall application in the Handbook W246. The foam panels have limited use compared to the cement backerboard, but are suitable for many applications.

4

I’m always squeemish where a substitution is proposed for a product that I don’t know much about, haven’t fully researched, and is quite different from what is in the documents. Specs are carefully coordinated for particular products; details are carefully drawn using them. This is not a knock on this particular type of product, but this sort of major change is something for which I always recommend a “no.”

5

I would agree with John’s comment above. sometimes there are coordination issues that were carefully thought out in the project that don’t immediately come to mind – but that the substitution completely ignores. This isn’t commodity product = commodity product. this is really a change.

6

Thanks to all. Your answers are most informative.

When considering approval or rejection of a substitution, I ask myself the following questions (and sometimes, to my surprise, I get answers).

  1. Is the product specified appropriate for the application indicated on the drawings? Sometimes the drawings are changed at the last minute and no one thinks of telling the poor scribe who writes the specifications that a change occurred.
  2. Is the substitute product better in terms of durability, combustibility, toxicity, etc. than whats specified for the application indicated? This may require time and resources to research.
  3. Is the substitute product acceptable to local authorities and does it have an ICC Evaluation Report number?
  4. What would the benefit to the owner be if the substitution is accepted, in terms of monetary benefit, aesthetics, and longevity?
  5. Has the product been used successfully in similar conditions as indicated in the past 5 years in the market where the project is located? Five years is the minimum length of time that we consider acceptable.
  6. Is the manufacturer reliable and will he/she stand behind their product if it fails (if youre old enough to remember Rezcon by JM, you know what I mean)?
  7. Lastly, but not that critical to me, what length and type of warranty is offered for the substitute product?
7

I would not reject a product just because it does not have an ICC-ES Evaluation Report. There are many good products that do not have evaluation reports.

If the product is addressed in the code all the local authorities need is evidence that the product complies with the relevant code provisions. These can typically be provided in the form of test reports.

If you had used a performance specification that referenced the code requirements then you do not need to talk to the building department at all.