Gate posts cracking - advice sought

[SimonB]

Hi. I have two roughly 8"x8" gate posts that I've re-used as post supports for a hammock. They were originally located outside but then pulled up and stored inside an unheated workshop for about a month. To make them more attractive I wanted to paint them with black external wood paint. To give a smoother finish and clean up the surface to better take the paint I initially tried sanding them. This was very slow so took 1-2mm off each face with an electric planer. Posts were then painted with at least two coats and then set in concrete.

The problem I now have is that the posts are cracking badly, see photos, with several quite deep, I'd say 2 inches or so. I had assumed that the posts were treated in some way, they seemed to have survived pretty well in their original location, I believe for at least a year. So taking a couple of mm off would not effect the integrity of the wood. I don't know why they have now cracked, have I opened up the surface enough to allow absorbed moisture to be released?

What I am not sure about is how the posts will now fare. If the entire post is not fully treated presumably they are now susceptible to rotting? Is there anything I can do now to prevent this? I was thinking fill the cracks but suspect I won't be able to do this well enough to seal all surfaces, and if the wood continues to dry out further cracks may develop or the filled areas will lose their integrity.

Is there a suitable product I could spray them with? I'm reluctant to go down this route since there are now climbing plants on them and plants all around them, but I could possibly put up a shield of some sort.

If they are liable to rot then in their current state, is anyone able to predict what their current lifetime is likely to be before they become too unsafe to hang a hammock from them with the risk of the bolt breaking out?

Any other thoughts/ideas welcome.

Thanks
Simon

 

[ondablade]

Some form of steel banding (maybe zinc plated 50X4 or a bit thicker if it's going to need lots of force to pull it back together - bolted in two halves and assisted while doing these up by clamps) at intervals down the length of the posts might well return most of the strength the posts had prior to their splitting. (it would be a little weaker due to the possibility of the split layers sliding along each other)

You could probably pour creosote or another preservative into the cracks before doing this to stop it rotting...

 

[OPJ]

How were these posts posts cut? If you look at the end-grain from the top, is the heart/pith visible? Although not ideal, I know it's often very hard (and wasteful!) to cut around the pitch when large posts like this are being sawn in the mill.

To be honest, the cracks don't surprise me. Look at many other timber structures around this time of year (and throughout the summer) and they'll be in a similar state... Yet, they're still standing! :wink: You'll probably find that, in the winter, these cracks begin to close up anyway. If it really is a problem for now though, sorry, I'm not sure what to suggest.

 

[StevieB]

Erm, its an 8" x 8" oak post. Its will outlast you before it rots all the way through unless it is sitting in a continually damp location. The cracks are timber movement, probably because of uneven timber removal from all sides of the post and most likely due to relieved stresses in the timber rather than moisture. Timber tends to dry 'in stick' at a rate of an inch a year as an approximation, so another 7 years and it should be dry

Will it continue to crack - probably. Is it unsafe - no, so long as the bolt is longer than a couple of inches into the timber. Would I worry about it - no. But if you do, get SWMBO to sit in the hammock first every spring just in case :twisted:

Steve

 

[Racers]

Hi,

I don't think its oak, it looks like pine to me that second picture is the giveaway, the even height branches.
Can you press your thumb nail in? if you can its pine, or you are a seriously hard turnip, then forget I said any thing :wink:

Pete

 

[maltrout512]

What I would do is buy some timberlok screws 150mm in length put them in the side of the post to draw the wood where the split is together. These screws are not cheap but have a short thread length approx 50mm to bite into the timber the furthest side of the split. If you see what I mean.

 

[OLD]

Modify the suspension fitting so the bolt /threaded rod goes all the way through the 8" timber and just use them there are lots of post and beam structures with splits working harder than your posts.

 

[SimonB]

Thanks for all the replies and ideas, some things to check and think about then. Bolting through sounds like a good idea, I'll look into it.