We have a deck railing system consisting of a 2X4 bottom rail toe-screwed into a 4X4 post and a 2X6 top rail that lays atop the post attached by screws driven vertically. The baluster(s) is a sheet of 1/4" tempered glass set in routed grooves of the rails. The wood is cedar and a pain to maintain so I have ordered replacement lumber that is made of HDPE (Bear Board or Lumberock, they are the same)The rail has various distances between the posts as well as 45 degree sections. I am thinking that I can build the top rail as the cedar is and that the posts will flex enough to take up the expansion and contraction (the 45 degree butt joints will probably not remain parallel through this) The bottom rails cannot hope to move the posts as they are too near the post mounting. I jhave been unable to find a bracket that would allow me to toe screw one end but a bracket that could absorb the expansion-contraction on the other end. I have considered having some aluminum right angle brac
kets made and powder coated. I would put slots on the surface to the rail and attach in a fixed manner to the post. I would do the calculations to cut to the optimum length and have to live with the gaps that are visible. I have called several manufacturers of HDPE wood and believe it or not, they don't have recommendations! I promised my wife I would do this and we just ordered the "wood" but I am at my wit's end trying to determine the right or best thing to do. The design needs to stay the same as currently configured. I just need to know how to deal with the temperature variations. I live in northern Michigan so the "wood will see from -20 degrees to 130 degrees.(The plastic gets hotter than the ambient temperature when in the Sun) Do you have any suggestions please? I'm not really confident about my top rail idea either.
Thank you,"

Well,it sounds like you are taking all of the important factors into account, and on the right track. Basically, I would think that if you design all of your holding grooves with dimensions that provide a little glass movement horizontally and vertically, you should be fine. In other words, you may have to router or dado your grooves deep enough to achieve some wiggle room, but close enough for the glass to not come out, of course.I sometimes like to use pieces or strips of EPDM (roofing membrane/pond liner)for cushioning, and to allow for expansion & contraction in similar situations. You might think about cutting some narrow strips of that to install in the grooves. This way the glass can swell & shrink, but won't rattle around in wind, etc. Also, keep in mind that the darker the color of the wood or especially composite material, the hotter it will get in the sun.

I hope I was able to address some of your concerns. Interesting project. Let me know how you make out or if I can be of any assistance down the line. :)


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Michael Romano


I can answer any questions relating to decks, porches, exterior stairs & railings, walkways, access ramps, pergolas, deck roofs, screen rooms, etc... These may include design ideas, footing to framing design & construction methods, various species of woods vs. composites & pvc/vinyl materials for decking, skirting, or railing applications. I also have expertise in various rain-free systems for under-deck storage & living spaces.


I have designed and built decks and many other types of outdoor structures for over 25 years for my own home improvement company. We also perform many other types of home improvements, including window & door installation, molding & trimwork, siding, basement finishing, siding, etc. Our main love however, is decks!

NADRA - The North American Deck and Railing Association. Several Small Business & Home Improvement Contractor Alliances & Associations.

I have written several articles over the years for,, and many other deck & construction related websites.

High School graduate. 2 years of Mechanical Drawing & Architecture classes. Vocational School graduate. 2 years of Construction Technology & Carpentry classes. Many years of reading, researching, and application in the real world.

Awards and Honors
I am certified by several decking manufacturers for expert application & installation of their products.

Past/Present Clients
Mainly local residential clients, and occasional commercial clients, including restaurants, nightclubs, office buildings, etc.

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