Deck repairs; into end grain

[John Neel]

I am repairing my deck. It has 2x4 top rails nailed into the ends of 4x4 posts. I will replace all the top rails. The posts, treated syp, are in pretty good shape. Replacing posts wouldl be a problem involving crawling in a narrow space under the deck and figuring out how to remove the posts that are nailed into some pretty tight spots. I can probably nail the new rails into a sufficiently strong area on most posts. However, the ends are cracked considerably on some posts.

People talk about firming up old wood. Would that work here? Could running some epoxy or something else into the end grain toughen up the posts? Should I consider using deck screws instead of nails? Any other suggestions?

Thank you for the help.

John

[Erik Christensen]

if the 4x4's are in reasonably good shape I'd put a cap on them to keep moisture out of the end grain - even with PT wood it will last a lot longer if capped

[Lee Schierer]

How high off the ground is your deck. If someone falls off will they likely get hurt. What are the chances they will seek compensation from you? First off I wouldn't use nails on a railing as they are too likely to pull out under a strain. I would use screws or bolts they hold better longer. If you attach your new railings to old posts in the supposedly sound areas and some one leans on the railing what will be the result? I think you'll be time and money ahead in the long run to replace the posts now and bolt them to the frame.

I was shocked last summer as I replaced the deck boards on our deck about how bad the galvanized nails had rusted. Most broke off rather than pull out because they were so thin. The lag screws were less than half their original diameter. It cost a bit more and took more time but I went with all new hardware and posts.

[Myk Rian]

It is suggested to use a plastic sleeve over bolts going through treated lumber.

[Robert Reece]

if you have to crawl in tight spaces, then you must be close to the ground. I think you don't need a handrail for anything closer than 24" or maybe even 30" (please check this). You might consider eliminating it. It makes for a nice deck.
If you aren't close enough to the ground you can build continuous steps all around. My dad did that and it looks great and functions great. Each step is about 18" or so and steps down gradually to terra firma.

[John Neel]

Thank you for the comments and suggestions.

The deck is 6" to 3' high. Little chance of falling off. I do need the rails to keep anyone from stepping into my wife's flower bed which surrounds the deck except 2 places where there is access via steps. I'm still thinking that sealing up the cracks would help. I like the idea of capping the top of the posts, but the 2x4 rail has to cover the ends of the posts.That would mean the cap would have a 2x4 over it. An epoxy coat over the end would also help seal the end like a cap would. So, I'm currently thinking to epoxy the tops of the posts and let the epoxy run into the cracks to help firm it up. Then screw the rail into the end grain. On the other hand, the previous nailing lasted 18+ years without pulling out. Other than someone leaning on the rail or resting a drink on one, there is very little strain on the rails. Maybe I just nail into the remaining firm wood. Anyone got a better idea?

Thanks again for your thoughts.

[Leo Devera]

I would go with the epoxy. I have actually used that in some projects to replace some weird parts of some cedar boards, and it works wonderfully. Fills all the voids nicely, and sets nicely. Perfect for this application.

[David Helm]

A picture would be helpful. I have built hundreds of decks in my time and have a lot of knowledge. If I could see how you are planning this I might be able to give you some help.

[Chris Vandiver]

I my experience, penetrating epoxy and then epoxy, will do the trick. Go to this website: http://www.smithandcompany.org/

They produce really good products for wood preservation and restoration. Just what you need for what your doing. Their product may be available to you locally.

[Kent A Bathurst]

Cracks in the ends of 4x4 PT posts is the nature of the beast. If the nails have been there 18 years, then the posts have ben there that long as well. The cracks won't induce faster decay than in the rest of the post, (the fastest decay is the in-ground part of the post) so I personally wouldn't worry about the structural performance. And, 18 years ago, the treating chemical was almost certainly CCA which was the best-performing, most-tested ever and you should have many, many years left in them. But, from a cosmetic standpoint - that's a personal preference. If you do feel like you want to reinforce them somehow, then galvanized lag screws (BORG) are the highest performance fastener - you could counter-sink the washer and screw head.

On the rails themselves - at 3' high, with a beer in hand and leaning on the rail, there is some level of risk of the rail giving way. Your repair plans are a very good idea. A 3' fall doesn't seem like much, but there are a lot of medical horror stories out there. There are plenty of replacement flowers out there, but fewer replacement vertebrae.

If it was my railing..........I don't know the exact design of your railing - there are many different designs - I'll assume your rails are 2x4, with the 2-dimension on top + bottom. I'd use a circular saw and cut dadoes/rabbets in the posts, and run the rails through those. Assuming the posts are 4' OC, I'd use 8' or 12' rails, spanning multiple posts. Coupla 3" deck screws into predrilled pilot holes (to prevent/minimize splits in the railing).

[Peter Quinn]

Smiths CPES will do a good job of consolidating the ends of the posts and driving off water that might be living in the end grain. Check that link above for Smiths, it works as advertised. Then a thicker standard epoxy can be used to pour in as a crack filler. By the time you're done, it may be cheaper to buy new posts, though obviously the application is easier. The only problem is the epoxy is water proof and will not move seasonally. The rest of the post is not water proof and will move, so eventually IME the post will shed the epoxy, the cracks will return, it is a temporary fix at best. If you had dipped the post ends in epoxy 18 years ago during installation, things might be different, but who does that?

I like the idea of changing the design, getting rid of rails that are face nailed into the end grain of the posts all together. That is how my deck is built, it is not a look I particularly enjoy, it causes water to be trapped under the rails on the top of the posts, it causes the rails to rot at the ends and the posts to check and crack, which they might do anyway, but they do it worse and faster.

I'd rather see the posts capped, and frankly boxed if possible, but thats more money and a whole different story, and then replace the rails with their face grain running vertical, and the ends landing just below the post caps. Now this may not be possible given the height the posts are cut at now. You might wind up with a railing below code height. Boxing the posts and putting blocking in the hollow top of the box would let you set the height of the hand rail to whatever you like. You do loose that "place to put my beer" platform this way, but you also loose the tendency of the rails to cup, hold water and rot.

[John Neel]

Thank you to everyone who responded. A friend happened to have a partial container of epoxy and the hardener to go with it. That settled it. I could try for free. When I started, I decided to wire brush the tops of the posts before applying any epoxy. After brushing, it turned out that the posts were not nearly as bad as I thought. What I saw as potential damage turned out to be detritus that just brushed off. I let one coat of epoxy soak in to seal things up and then applied a second coat to fill the holes and cracks. It worked very well and I am looking forward to putting it all back together. I keep finding uses for epoxy. You all keep teaching me.

Thanks again.

John