Landscape Carpentry

[Xamonas Chegwé]

Yeah, you should replace all of the posts.

It is not our policy here to replace posts, however tired, worn or lame. We leave them here as an example to others.

[Bella Fortuna]

Yeah, you should replace all of the posts. The upper section looks solid enough. Tough to tell by the pictures. I see some dark parts around the lag bolts up top though, is that just moisture or is the wood soft there?

Are the posts set in concrete? How deep do they go? Does code/soil and weather conditions there require concrete? It's the best solution in most places, but where I live setting posts in concrete is just a bad idea.

Mung Bean's method is an excellent temporary solution, but that much work for something that should be fixed properly within a year or so seems kind wasteful. The thing is that if it fails and comes down by itself, it will damage your patio furniture and possibly your house.

Posts are not set in concrete - therein lies the inherent problem, I expect. No idea how deep they go. With one completely not touching the ground and the one next to it looking close to that state, it seems rather pointless to find out. The soil here is solid clay - squishy perpetually wet in winter and hard as stone in summer.

Things look wet because we just had a couple of days' storms...

[JimC]

Unless made from H4 treated pine (& maybe even if they are), posts are best sitting in a post stirrup, itself firmly anchored in concrete, particularly if they are structural supports for some sort of roof. Bella, in a time of high unemployment, you could probably find a young, jobbing carpenter who could replace them reasonably cheaply.

A young bloke, with rippling muscles, who works bare-chested in the Californean sun, glistening with sweat...

[Mung Bean]

Sounds like replacing all the posts is really the way to go for this one. The good news is that it's an easy job that requires bugger all in the way of brains, skill or tools. Bad news is that it will still cost money, so it comes down to what materials and labour cost over there and how much you have available to throw at the problem.

Looking at those pix I'd say the weight is stuff all, so you could prop it up with just about anything while the posts were being done. Anyone who has owned a circular saw for six months or more and still has all their fingers and toes should be able to handle this job. If it takes them more than two days they aren't trying. Set the posts in stirrups as suggested by JimC and if you want added protection slap some tar on the bottoms and in the bolt holes.

[Reverend Blair]

Posts are not set in concrete - therein lies the inherent problem, I expect. No idea how deep they go. With one completely not touching the ground and the one next to it looking close to that state, it seems rather pointless to find out. The soil here is solid clay - squishy perpetually wet in winter and hard as stone in summer.

Excellent. Clay soils and concrete don't go really well together. The clay holds the water and it hydraulics the concrete out of the ground when/if it freezes. Concrete also loves water and expands and contracts as it gets wet and then dries, abrading the post and promoting rot. This is really only a problem in heavy clay soils. Everywhere else concrete is the way to go.

I suggest digging an eight inch diameter, three foot, six inch deep hole, putting about four inches of crushed limestone in the bottom, laying a piece of pressure treated 2x6 in the bottom to act as a footing, then placing the post on top of it. Backfill the hole with crushed limestone while tamping well.

If you want to use concrete, or if code requires it, and you have clay soil, dig a ten inch diameter hole, put six inches on crushed limestone in the bottom, then use an eight inch diameter sono tube to retain the concrete and post and backfill around the sono tube with crushed lime. The crushed limestone provides drainage. Use a post concrete or a fibreglass additive, since there's no room for steel in post holes.

To remove the old posts, just wrap a chain around them and use a Jackall to pull them out of the soil. For the broken post, you'll have to dig a bit, but once you get down to solid wood (it likely won't be rotten a few inches down), drive a couple of lag bolts into it, attach the chain to those, and jack it out of the ground. If you want to reuse the old holes, clean them out with an auger and whether you are using the old or new holes, make sure that you go at least three feet, six inches deep. You need to have at least three feet of post underground.

[Bella Fortuna]

Jesus... this is way out of my league! Thanks for the suggestions. I can't afford to do anything with it right now, but will save your ideas for when it moves to the top of the 'must do' list.

[Reverend Blair]

It's actually all pretty cheap and easy, Bella. If you do the work yourself (or talk a couple of friends into it) the beer is likely to cost more than the materials. You are really only buying a few posts and digging some holes after all.

Speaking as one of the guys who always gets the call when there's a project afoot, it's important to remember that people will do things for beer that they would never do for money. That's the real secret of the pyramids.

[Mung Bean]

Bloody hell Rev, you septics are a weird bunch. Over here we'd do it differently in any soil, but then we drive on the other side of the road so go figure.

Standard operating procedure over here, as long as you're not in a cyclone zone, would be a hole around two feet deep and sixteen inches across. Fill that with concrete and set a galvanised stirrup in it. Drop post in stirrup and bolt in place. Keeps the post out of the ground so rot and termites are no drama, and replacing the post is a piece of cake.

Oh and the building inspectors over here would totally freak if you suggested using a bit of wood as a pad at the bottom of your footing. Not saying your way doesn't work. It's just interesting comparing the different ways things are done.

Also if you tar the end of the post that is a great help in keeping rot out long term. I always tarred the tops of joists on decks and they last one hell of a lot longer that way.

[Reverend Blair]

Yeah, we don't build that way in North America, Mung. Perhaps we should, but we don't.

Concrete in clay is troublesome though, no matter where you are. The clay holds the water, the concrete sucks it up. That doesn't hurt the concrete, but it hurts any wood set in the concrete. If you live somewhere that it freezes, a large concrete footprint just gives the ice more to grab onto. That leaves you digging bigger holes and trying to drain away water by surrounding the concrete with crushed rock, which seriously undermines the point of putting concrete in at all.

There are other options...bell-shaped piles and footings, for instance...but they are cost prohibitive, especially for small projects.

As for preventing rot, I suggest pressure treated lumber with end-cut treatment in any area you use a saw on.

[JimC]

Yeah, we don't build that way in North America, Mung. Perhaps we should, but we don't.

Concrete in clay is troublesome though, no matter where you are. The clay holds the water, the concrete sucks it up. That doesn't hurt the concrete, but it hurts any wood set in the concrete. If you live somewhere that it freezes, a large concrete footprint just gives the ice more to grab onto. That leaves you digging bigger holes and trying to drain away water by surrounding the concrete with crushed rock, which seriously undermines the point of putting concrete in at all.

There are other options...bell-shaped piles and footings, for instance...but they are cost prohibitive, especially for small projects.

As for preventing rot, I suggest pressure treated lumber with end-cut treatment in any area you use a saw on.

A large part of the stirrup option in Oz involves reducing termite attack, they are very active down under...

[Reverend Blair]

Pressure treated lumber, or types of lumber that are naturally resistant, is what gets used for that purpose here. Stirrups do get used to some extent, but aren't really common practice except in areas where code requires it.

Codes in North America are a mess. In the city I live in there are actually different codes for different parts of the city and so many grey areas and interpretations that inspectors regularly contradict each other. Sometimes there's a reason for it...the weather here is a lot different than the weather in California, and we don't get earthquakes here. Sometimes it's just stupid...you are supposed to use 6 foot piles for wooden decks here, even though the deck and house will still shift at different rates and in different ways. The easiest solution to that shifting is simply to use ground pads to support the deck and adjust for shift by jacking up the deck and using gravel to re-level the pads. The result is that nobody gets permits for decks. Why does this rule exist? Well, it was imported from areas with sandy soil and the concrete industry has a lot of political pull here.

So with any construction it's important to check two things...what local codes are and what local common practice is.

[hadespussercats]

Landscape carpentry is just a fancy term for the crap you build in your yard. Mostly it works out to be fences and decks, but raised flower beds, wood retaining walls, picnic tables, wood gazebos, wheelchair ramps, sheds and rough housing for livestock, and even a free-standing stansion for two milk cows are all things I have some expertise in.

With the gardening/building season coming up, I thought I'd offer to answer questions anybody might have.

Have you even noticed that Roger Cook, the landscaper on This Old House, is missing part of a finger?

Reminds me of Wood Shop teachers holding up their partially digit-less hands and telling the kids to be careful with power tools...

[Reverend Blair]

I work repairing power tools a couple day a week. I'd say half of our over-forty customers are missing some bits. I'm not sure if the younger guys are more careful, or just haven't been around long enough to have reduced their counting options.

The landscaper on This Old House is one of the few TV how-to guys I still pay attention to. Most of them are forced to cut so many corners because of time constraints that they really don't show you much. Landscaping tends to be simpler though, so his segments tend to be way more informative.

[JimC]

I work repairing power tools a couple day a week. I'd say half of our over-forty customers are missing some bits. I'm not sure if the younger guys are more careful, or just haven't been around long enough to have reduced their counting options.

The landscaper on This Old House is one of the few TV how-to guys I still pay attention to. Most of them are forced to cut so many corners because of time constraints that they really don't show you much. Landscaping tends to be simpler though, so his segments tend to be way more informative.

Our very own Woodbutcher is one of the missing digit crew...

I have been working in the shed with my 15 year old son, and safety with power tools is high on my agenda... (all go through quick shut-off power leads, for example...)

I did a big modification on my passionfruit vine support:



The more I tried to tighten the wires, the more the outer posts leaned inwards... (too dumb to think of that at the beginning... ), so I have replaced the top wire with a couple of struts (first loosening all the wires), then the wires tighten perfectly against the compression of the wood...

Will post a pick of the finished product later...

[JimC]

OK, here is the finished product (which is how I should have built it in the first place... )



Now to dig holes, put in compost and fertiliser, and plant 2 passionfruit vines...