When wooden posts are used for railing it is best to go with pressure treated 4 x 4 posts.
How to attach railing posts on a flat roof.
Cut the post to the desired height of the railing the width of the framing you will attach it to and the thickness of the decking minus the thickness of the top cap if there will be one.
To counterflash the uncured rubber you can either kerf the post and counterflash using copper or aluminum or box in your post thereby covering the post and rubber.
Roofing contractors normally don t want to deal with the installation of post and railings.
Snap chalk lines on the roof that define the line of the handrails.
Measure from the edges of the roof and mark the line of the handrails at several points.
Access the roof using an extension ladder.
Here we show posts for a 36 inch tall railing which is common.
For handrails at one or more edges.
These posts should be fastened to the rafters with bolts and nuts.
Normally a carpenter is best suited for this job.
Staggering the holes avoids splitting the post along the grain lines.
A threaded rod between one plate screwed to the framing and another plate at the top of the post firmly connects a hollow newel to a rooftop deck.
How to attach railing posts to a flat roof.
A schematic diagram of a post on a roof.
Once the plate and rod are installed i stand the post in place.
Usually some scribing and fitting are needed to make it stand plumb without wobble or lean.