Another pier thread.....

[Shelster1973]

Seems Mrs S may be getting worn down by my persistence at astronomy....and has agreed in principle to me building a pier, but as always there are some rather stringent rules and caveats that need to be adhered to so as to get full planning consent.

The main one is is need ot be fitting in with the garden design which is going to be oak raised beds and the majority decked, so as such can't see me getting away with a concrete or steel pier.  I could go down the line of this and then clad in oak, but was wondering what peoples opinions of wooden piers are?

Will not be a tall affair, was thinking of 1-1.2m in height above ground, which would include the mounting plates too.  All I am adding to it is what is below in my signature, so not a huge load.  Size wise was thinking an 8" square gate post (either oak or a treated gatepost to save on rot where it meets the ground)

Burying wise was going to go at least the height above below the ground and then also for the upper part of the buried bit, extend this area out and put an increased concrete area around this, mainly for securing but also to provide a more substantial area to walk on.  May use decking off cuts to make base area look tiddly

Would this be suitable for my needs?

Have seen people say that there will be changes to PA due to the wood expanding and shrinking with changes of season, but this can be overcome surely with a slight tweak every month or so.  There was also talk of the virtues of timbre to be able to dampen vibrations......

It seems like ti may meet all the needs and then mine too and also be a heck of lot easier to construct (and cheaper) then going dow the cast route.

Cheers

[Dr_Ju_ju]

one this to keep in mind is access\route for power, mains?, and signal\computer cables etc. and some form of secure weatherproof box at the pier, to keep them in...

Julian

[Shelster1973]

Had thought of that side.

Power will be ran out to it from existing external supply.

Cabling wise am wanting to go for a full USB setup so am hoping to get it down to oine USB cable from laptop to hub and hten cables spider out from there for camera and guidecam.  Wil need power for that too so looking at mounting double socket on the pier.  Laptop will be sitting on teh lower level of the garden on a bench with it's own supply.

[Tinker1947]

If you go the wooden pier route a 6" X  6" Oak will do, make sure its not green oak, as this will move, if its softwood then a 8" X  8" would be better, treat either with Creocote substitute this is oil based and will help repel water, i used pea shingle to fix the post in the ground went down 4' poured and tamped the shingle as it went in, make for a solid pier and allows for drainage, there easy to get out just hoover up the shingle and lift the post out.....

[Shelster1973]

Cheers Tinker, some good advice there.

Where abouts did you get your oak lump from?  Local timber merchants or online supplier?  We have a hardwood supplier just down the road so amay go and see what they have there.  Don't suppose you have a list of parts used in making yours do you?

So it was only secured using pea shingle then? no concrete?  Was thinking baout getting 4' down..the 1st foot will be ok as will be going through clay...not looking forward to the last 3 feet as this will be through compacted limestone where the developers have levelled out the upper tier of the garden.  Can see some choice expletives coming on.

[Tinker1947]

There is a hardwood sawmill in Norfolk i use, 6" X 6" works out around £10 a foot to buy here it could vary a lot in different mills, my soils is silty nice and soft the 4' deep hole took around 15 minutes with the silt bone dry that deep. i have some images i took when building....used 16mm studding screwed into 15.5mm holes,  I milled the piece of oak for the mount to attach to

[Shelster1973]

Looks very nice indeed. We only have the clay as that was the imported topsoil. Hopefully the compacted layer won't be that deep. Have emailed the timber yard and will see what they say. Quick look online shows about £55 for a 8' lump

Do you do commissions for pier tops

[Shelster1973]

Small update, no pics yet....

Have been doing some research and will be going for a 200mm x 200mm pier but made up of 4 100 x 100 posts glues together.  Have been speaking to a guy in the states about it and his has been in for 10 years and has no issues with warping and shifting, bar a small PA check and fix each year. which will do me.

Also have stated a dig for the post and had some mixed findings.  The first bit through the clay was as crappy as expected and then the bit down to 70cm depth went failry easy, a bit clarty and sticky, but not too bad.  It was then that I hit a cloth membrane which I have yet to go past.  Not sure what lies underneath to be honest, but am hoping for some easy to remove soil.

Have also decided to change height of pier too.  With my manual digging have realised that going down the 1.4 metres I mentioned previously wold be unachievable as the hole would then be about as deep as me and I would not actually be able to reach the bottom to pull out the muck.  Am now going for a 1 metre hole and will be using 1.8m posts.  This puts more of the post underground than above (55:45) and so will reduce the amount that the pole can move above ground.  It also reduces the price coinsiderably (which is a big factor in getting this through planning) and makes it easier in man handling the posts and more importantly getting them back from the timber yard in my Fiat 500.  Securing will be with Postfix quick set concrete topped off with the half bag of concrete I have left over from my rubbish attempt at puting in hard standing for tripod feet.

All the metal work is now complete and ready to be mounted.  Looks like this will be March project now

[NickK]

probably worth given the timbers a good soak in preservative if they're in the ground and make sure there's no standing water in contact.

I used a post hole digger - they work but at some point you need to lever the jaws close and the arms make contact with the side of a narrow deep hole. I got to about a meter in sand in about an hour.

[Shelster1973]

Cheers Nick

Posts are pressure treated and tanalised too...but no harm in giing thema damn good saoking in more preservative.

Have been poking my eye in the hole already dug and it drains very quickly, even with the downpours of yesterday, so should be good for whenthe post is in.  WHere the post meets the ground am going to have sloped sides away from the post so that there will be no chance of water pooling around the base.

Did think of getting a post digger but seems a bit of an outlay just for the one hole..will persever with a spade and hands.

[Earl]

is it worth soaking it in old engine oil?

[Tinker1947]

You could use Pea Shingle to hold the post in place, it allows the post to breath and water to drain away, there is the benefit of no cement mixing, if you want to remove the post simple suck the shingle out with a industrial hover, mine is in a 4' deep hole and rock solid......

[Shelster1973]

Yeah thought of that but can't see me digging down 4 foot. Nor planning on removing it so should be OK with post fix

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[Gina]

Concreting wooden posts into the ground is NOT a good idea   I have examples of 4" fence posts that were concreted in and have rotted off leaving a mass/mess of concrete in the ground and needing new posts put in away from the original position.  This in itself causes problems  

Wherever timber comes into contact with concrete (or brickwork) in the ground, it wants damp proof barrier to prevent rotting.  If you want to use concrete, use it to fix a metal post holder such that the bottom of the post is well above ground level and can drain/dry and doesn't sit in water.  OR continue it up into a concrete pier OR make a block with cast in lugs and bolt a steel pier onto it.

[Shelster1973]

Latest update....

Have got the wooden posts and joined them all together to make me an 8x8 post.  Had no joy getting through the cloth layer that I came up against when digging, so have sunk the post in and will cut it down once the concrete has gone off.

The first postcrete was put in yesterday and when that goes off will be putting in a further layer around the post so as to give me something to walk on when putting the tube on and off the mount.  This will be sloped away from the post so any water that falls will run away from the post.  Will also be tapered up where it meets the post at a sharper angle so as to completely minimise the risk of standing water around the post.

Did a quick 'engineers eye' check on it last nigth when there was a brief break in the clouds and looks spot on for north alignment.  May possibly need a smally tweak but have play in the pier head to cope with that.

Hoping to have the remaining groundworks done by next week and then hopefully if the skies play ball, get 1st light when that has cured and set.

Will get a few pics of where I am at present when I get home later on.

[Shelster1973]

As promised a few pics of where I am at present.

The 1st two were taken yesterday and show pier with basic holding postcrete in and also the level (close enough for government work there I think)

The last three were taken today after I had laid the extra postcrete to form the walk base and slopes on the pier sides.

Intentions are to cover the concrete in decorative stones to the level of the mud...sorry, garden so as to camouflage it a bit.

Mrs S gave me a 'WT........??????'when she 1st saw it and then came out with how she could not recall our discussing it and her green lighting the project.  When I went back she then had slight memory recall but came back with ' was not expecting it to be so solid.......'.  Will blend in better when we actually get round to decking the mud and also putting in the raised beds and artificial grass (yep I know, but am lazy and also have no where to store a mower)

[RogerTheDodger]

I had similar constraints so I built a brick pier at my last house, during the day it had a sundial on top.

Now that I have moved house, I will build another

[Shelster1973]

Bit more progress today.

Got the stones down and also mounted the top plate too.

Did a test fit of the mount to see what it was like too.

As it stands, the dovetail plate is just about my eye level, so think I may need to bring the steps out with me when I do my setting up.  Good part of that is that it clears the view a bit over the roof of the house so can see the western skies better.

Now just need a clear night and will be away.....

[Shelster1973]

.....quick add.  Am very tempted now to replace the rear elevation adjustment with an Allen headed bolt so as to make it easier to sight down the polar scope.

At present I will be taking the actual mount head off each time as do not have a waterproof cover for it yet.  That will require a bit more saving so that I can get one that is suitable.  Will then be permanently fixed onto the pier and just the OTA and counter balance weights will be moved each time for imaging runs.

[michael8554]

Since you went ahead with concreting the post in instead of pea shingle, I would check that the concrete next to the post is well above the rest of the garden, because it looks like you have created a nice soak-away from the mud to the post.

Michael

[Shelster1973]

Is OK. Had heavy rain here over night after I had put the concrete down and was no standing water in it. Seems odd as garden is effectively a big clay lump but it drains surprisingly well.

Will keep an eye on it though. The raised angle bits are above ground level too

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[Gina]

You might have a problem with one side of the post getting wetter than the other causing the timber to curve and upset your PA.

[Shelster1973]

Had a look this evening after the really bad rain here earlier and no puddles around the pier and only water that I could see was where it had just got generally wet.

May go for an outdoors paint on it if I can find one that will suit the scheme that has been planned.

Cleared up a bit tonight, but not enough to get set up.  But did grab a few shots with my camera just sat on the pier so that I can get an idea of views.

North

East

South

Did try and get a westerly but clouds have now rolled in

[NickK]

That street light (East) could cause blooming on CCDs for longer exposures but unless you're starting that low in the east each night you may be ok.

[Shelster1973]

The light to the east is an insecurity light in the garden. They turn it off after about 2200 so not that bad really.

Will be a very long time before I venture into the world of ccd imaging. Only two options for getting there.....win the lotto or someone kindly donates me a ccd to use. Don't think either of those will happen anytime soon

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