Railing Solutions For Deck Over Dry Living Space

by M. Larose
(Alberta)

I have an upper deck at our cottage with a finished living space beneath. The deck sits directly over the great room .

There is a Dura-deck membrane that covers and seals the surface of the deck. I have several concerns.

1. How to mount railing posts without risk of leaks.
2. Protecting the view.
3. Snow Load. Must be able to remove excess snow (live in Alberta).
4. The upper deck can be exposed to wind gusts off the lake

I am interested in the cable railing format and could side mount the posts along the fascia of the deck. However along the one length we have an eves trough that captures the run off that sits under a 2" or so deck overhang all along the length.

I have been unable to come up with a solution given the challenges. Could you please help resolve these issues.. perplexed and procrastinating.

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Editor's Comments:

A long term suitable railing solution for your deck does require some thinking to get it right. Duradek vinyl membrane is a long term proven waterproofing solution and if installed properly will last a long time for you.

Vinyl membrane over living spaces below it must be 60 mil (60/1000ths of an inch) material and double or even triple welded but if done so will be very safe.

Installing railing over top of this kind of surface has to be thought through very carefully because if you do it wrong you will have a lot of problems none of which are easy or inexpensive to fix.

Surface Mounted Railing On Duradek

This method should include planning in advance of applying the vinyl membrane. Post locations should be identified and extra blocking installed between the joists wherever a post will go.

A high density plastic base with chamfered side and a flat top should be glued and screwed down onto the plywood substrate. Then the decking crew will start installing the vinyl and layer it and lap it and weld it over the elevated bases.

This provides a waterproofed and elevated surface area that the post can be anchored to. The elevation ensures water never pools around the base of the post and if the post is attached properly and sealed with a gasket and caulking you have the best possible scenario for a surface mounted railing.

Fascia Mounted Railing

This is a very popular technique and removes the risk of the post base attachment locations ever leaking. But it also means you have to build your deck with reinforced rim joist to joist connectors because the railing will now be connected to the fascia.

This is simple enough to do if done during the initial construction. Not so easy if done after the fact.

Complicating your deck is the fact is you want to use eaves trough to collect rain water. Obviously the intermittent posts along the fascia will conflict with the eaves trough.

One possible solution if the fascia is wide enought is to secure the eaves trought lower on the fascia just below the posts. This may or may not be possible.


Protecting The View

The best railing choices for a view property are glass panels or balusters or a cable rail. Be sure that cable railing is permissible in your area. Some jurisdictions are opposed to them if they can facilitate climbing. Other areas are fine.

Snow Load

With a cable railing you should be able to shovel the snow and push it through the cables without trouble. Any other panel rail system will post more challenges because of the smaller space under the bottom rail.

If it is a significant problem perhaps you can remove one of the railing sections but then you have a dangerous situation where part of the railing is missing and for how long.

One type of railing connector for wood railings that can be more easily installed and removed is the Shadow Rail Connector. But it does not sound like you are looking for a wood railing solution.

Wind Gusts

A railing with a solid panel such as glass will feel the brunt of a strong wind more than balusters or cable rail. So this is something you will have to determine yourself.

Hopefully this discussion has been helpful for you. If there are any builders who have had more experience in this area please offer your comments.