Which epoxy for glueing composite decking to pressuretreated wood?

[Michael Schuch]

The front stairs to my house rotted out so I am in the middle of replacing them. I don't want to have to replace them in another 20 years so I selected materials that "should" outlast me. I am using composite decking for the risers and steps and powder coated steel stringers. To mount the facia to the metal stringers I choose 3M 5952 VHB double sided tape. This is the same tape that Florida department of transportation adopted to mount their street/highway signs instead of using mechanical fasteners (nuts and bolts). According to a 3M article Florida DOT found mechanically fastened signs blow off in hurricane conditions while signs that are simply tapped on stay put.

521504

I do not have enough surface area to bond the upper part of the facia to the stringers with tape.

521505

I have decided to cut blocks of pressure treated wood to fill in the upper portions of the stringers.

521506

521507

The lip on the block will be plenty to keep the upper part of the facia from warping away from the stringers.

What epoxy should I use to secure the pressure treated blocks to the composite facia boards? There will be plenty of surface area for the epoxy bond.


FYI: I will be bolting and taping the steps and risers to the stringers.

521508

521509

[andy bessette]

Instead of epoxy I would use 3M 5200.

[Michael Schuch]

Instead of epoxy I would use 3M 5200.

3M 5200 sounds promising and would be a lot easier than mixing epoxy. I will read up on it!

Have you used 3M 5200 before? What did you use it for? I assume it worked well for your application?

[andy bessette]

I use it for permanently bonding wood, fiberglass and metal on yachts.

[Maurice Mcmurry]

Epoxy specifically for for plastic might work. Silicone sort of works. The next thing I will try is 3M 5200. Composite decking is wood fiber and resin, usually polypropylene. Some brands have an outer color layer of 100% resin. I have never had luck gluing composite decking. It expands and contracts significantly. My go to epoxy for plastics are the stinky epoxy for Corian and the plumbers epoxy stick putty specifically for PVC and ABS. There is also a stinky automotive version for plastic tanks and radiators. That is an impressive undertaking! I guess I am glad to see that CCA treated wood is readily available again. ACQ treated has been a disappointment.

[Lee Schierer]

Our front deck has composite decking on the deck and the steps. The step frame/stringers are made of treated lumber. The decking is attached to the stringers with Simpson Strong Tie galvanized angle brackets (https://www.homedepot.com/p/Simpson-Strong-Tie-2-in-x-1-1-2-in-x-1-3-8-in-ZMAX-Galvanized-Angle-A21Z/100375047) and #8 x 3/4" stainless steel pan head screws from the bottom. No fasteners are visible. The treated lumber rests on the concrete side walk. The steps were built in October 2005 and are still solid.
521513

[Tom M King]

Another vote for 5200, and yes I have used it before, many times. I've been involved with boats longer than the 51 years I've been building. Just hope you never have to get it apart again.