ACM panels, VHB tape and waterproof seam

[jwiereng]

Please post if you have experience with using VHB tape.

I am wondering if a waterproof seam could be made by butt joining 2 ACM (DiBond) panels together with VHB tape under and centered on the joint with a framing member underneath.

See attached photo. Teal is ACM, red is VHB, Grey is frame

 

[luthj]

Assuming you use a VHB with the right adhesive/thickness for the substrate, it will work fine. There are skyscrapers with windows glazed/attached with VHB products.

 

[john61ct]

Sealant still required for waterproof joins.

Which may also be adhesive, or not.

 

[Martyn]

Sealant still required for waterproof joins.

Which may also be adhesive, or not.

The UHB tape will form a waterproof seal so long as it is applied correctly, all parts are clean, and an adhesion promoter applied.

 

[john61ct]

With a homebuilt, personally I'd want to apply a good permanently flexible sealant, unless there was a strong reason not to.

 

[jwiereng]

The UHB tape will form a waterproof seal so long as it is applied correctly, all parts are clean, and an adhesion promoter applied.

thanks for the reply. In your opinion, is the method shown in the diagram an acceptable way to form the seal where two panels meet?

 

[jwiereng]

With a homebuilt, personally I'd want to apply a good permanently flexible sealant, unless there was a strong reason not to.

Thanks for the reply. I am led to understand that the VHB is essentially permanent, the viscoelastic foam provides substantial flexibility. check out this video

 

[Martyn]

thanks for the reply. In your opinion, is the method shown in the diagram an acceptable way to form the seal where two panels meet?

Well it’s one way of doing it for sure. It will depend on the thickness of the panel, if you are using a thicker panel there maybe some extrusion that you could use to hold the panels together, sometimes extrusion and mechanical fasteners are used. If you are using thin dibond then this is as good a way as any.