My father just built some new deck railings for us as our old ones were rotting and falling apart. I want to attach a picture but do not see an area to do so... The posts are surface mounted using a bracket attached in front to the support beam at the edge of the deck and the other side just the deck floor. We want to know if there is something we can do to offer more support/reinforcement as the span is 5 and a half feet between posts and we are worried that it will not hold up if someone falls against with a lot of force. The spindles are spaced about 5 inches apart and the rails total a height of 41 inches. My father will not take them down so this needs to be something we can do in addition to what he has currently done...

Given that you must work with what you already have, you have only two options.

One, you could add an "L" shape bracket , screwing it into the deck and the side of the post. That will help some. It will make the joint between the deck and the post stronger but it will not do much to eliminate the movement at the top of the rail. It will never feel good. It will of course be unsightly.

The other option is run a lag bolt up from underneath through the deck board. From underneath, drill through the deck board and into the post. Screw in a lag bolt with a large washer. The longer the lag bolt and the larger the washer the better. Again this will strengthen the post connection but will not eliminate the movement at the top of the rail.

Hard to say without pics or size of brackets in place.

You should check the local building code... from what you explained, this may be an unsafe condition.

If main support will be from interior L-shaped bracket... make it heavy duty and bolt it to the floor and post vs screws.

Im sorry, I meant screws, he attached with 3.5 inch deck screws..

So the post are attached to the side of the joist or the band board. That should be OK. If it does not feel secure to you, drill holes through the post and the band board and bolt together with carriage bolts, large washers and nuts. Not lag bolts.

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