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Working with Concrete Block
Posted: Tue Mar 19, 2019 12:14 pm
by IrishPeter
This may be a series of questions induced by lack of sleep and coffee, but I have to build a raised section for the Far End Tramway. So, does this sound workable?
I need a series of short pillars (approx. 18" tall) to hold up a decking board superstructure, and the good old 16" x 8" x 8" concrete block up on end, set on a concrete foundation pad, comes to mind. Couple of questions about concrete block.
1. What are they like to drill?
2. I am assuming the need to use angle brackets to attach the joists for the superstructure, and that the supports should be at 3 to 4 foot intervals.
Any comments about decking boards as a foundation for a railway. I am anticipating an operation life of about 15 years, so I would imagine that avoiding things like ballast and felt which prevent the boards from drying out would assist in meeting that goal.
Cheers,
Peter in Va
Re: Working with Concrete Block
Posted: Tue Mar 19, 2019 12:27 pm
by -steves-
Peter
Not sure about drilling these particular concrete posts, but personally I would not be drilling any concrete without an SDS drill, they go through it like butter. Only down side if the concrete is brittle at all, it might shatter bits off it. Sorry, that's all I have though I am sure others will have more for you
![:)](./images/smilies/icon_smile.gif)
Re: Working with Concrete Block
Posted: Tue Mar 19, 2019 1:45 pm
by philipy
First question that comes to my mind is, what exactly do you mean by "concrete block"? The high density blocks are a pig to drill without the right gear, as Steve has suggested. OTOH, the lightweight aerated blocks are as easy to drill and cut as falling off a log.
Re: Working with Concrete Block
Posted: Tue Mar 19, 2019 1:52 pm
by IrishPeter
I was thinking of the standard perforated block used in construction. Not too bad to drill with the right bit and a hammer drill, but a material I have stayed away from in the past. I don't enjoy the racket from drilling operations, and was only contemplating it this time due to the relative small number of supports required - about a dozen.
The other idea that has occurred to me, or rather John over at the FBGR, was using plastic downpipe for the posts, and using post-crete to concrete it in. This strikes me as being a lot less of a pain in a rather sensitive place, but I will have to have a look at the sort of plastic downpipe used in these parts. The aluminium stuff is certainly a bit lacking for any purpose other than being used as down pipe.
Cheers,
Peter in Va
Re: Working with Concrete Block
Posted: Tue Mar 19, 2019 1:56 pm
by Peter Butler
I agree with both comments above, concrete blocks, (of the UK kind), are easy enough to drill with the right equipment, however, keep away from edges as that is where fractures become likely, either from vibration or frost damage.
Personally I would still use a felt covering. If the timber is treated it should give your life expectancy (not yours, the timber!) as there should be less damp penetration and adequate circulation beneath to allow it to dry out.
Re: Working with Concrete Block
Posted: Tue Mar 19, 2019 2:19 pm
by IrishPeter
Peter,
I have heard a cacophony of different views on whether or not to felt. I was going to object to felt on the grounds of our humidity and rainfall, but when I saw you are in West Wales I decided it was a case of 'never mind!' We are warmer than West Wales but otherwise the climate is similar, so I imagine anything you can get away with there would probably fly here too. My number one thing to avoid is wood in contact with the ground mainly because of rot, but also because of termites. The termites are the major reason for trying to find some sort of non-edible support for the railway. Once I am back on ground level things will be a lot easier, as I can revert to my usual construction methods.
Thanks,
Peter in Va
Re: Working with Concrete Block
Posted: Tue Mar 19, 2019 2:22 pm
by philipy
Peter, I've used 4" square brown plastic downpipes set in Postcrete for supports in some places - works fine. I cut some wooden plugs to fit inside the posts for the top 2 or 3" and then screwed timber crossbars to the outside, through the post wall, into the plug, to carry the trackbed. Allows a degree of adjustment,saving the need to cut the posts at exactly the right height and perfectly horizontal at the top.
Re: Working with Concrete Block
Posted: Wed Mar 20, 2019 2:14 pm
by IrishPeter
I am liking the plastic downpipe idea more and more - it somehow seems more efficient. How deep do you go below the surface? I would be inclined to go about 8" to a foot depending how far I could get down before hitting a tree root or a rock.
![:D](./images/smilies/icon_biggrin.gif)
This is the first time I have had to build a raised section on one of my lines, so it is all a bit new.
Peter in Va
Re: Working with Concrete Block
Posted: Wed Mar 20, 2019 2:23 pm
by philipy
IrishPeter wrote: ↑Wed Mar 20, 2019 2:14 pm
How deep do you go below the surface? I would be inclined to go about 8" to a foot depending how far I could get down before hitting a tree root or a rock.
Thats about what I did. Make sure you get the Postcrete underneath it so that it sits on a raft to spread the load and I poured a few inches of dry mix down the inside, from the top, so that its sitting inside concrete once it cures.
Mine have been stable for about 4 or 5 years now.
Re: Working with Concrete Block
Posted: Sat Mar 23, 2019 1:32 pm
by IrishPeter
It is usually called composite over here, and is readily available, but quite expensive - around three times the cost of pressure treated timber. Treated decking boards are supposed to have a life of 10 to 15 years here, so I am keeping in mind the fact that replacement will come due somewhere around 2030/1. The snag with the composite boards were that they were only available in 12' lengths, came in 96 different varieties, and ended up being out of my budget for the whole project, though I may still use them for the section closed to ground level provided I can get them cut in store so I can get them in the back of a Toyota Camry. The other influence was that relatively little of this line will be on decking - just the main station area, and the upper terminus, if I can manage to route the railway around the back of the flower bed - around 100 sq. ft. in total. The rest will be what is for me orthodox ground level construction - i.e. a trench full of chippings with the track embedded in the top layer loosely fixed at intervals to piles.
I am not completely happy about the solution with the decking boards, but given budget constraints, etc., etc., it was the point at which money and ambition could be best reconciled with one another! I definitely did not want to set the posts again, so they are PVC downpipe, which is cheap enough anyway.
Peter in VA
To felt or not to felt? - that is the question!
Posted: Tue Mar 26, 2019 4:07 am
by IrishPeter
I have not done the raised track bed thing before, but I am currently construction a raised platform for the main station of my line. This is constructed of 5.5" by 1" (actual) deck boards carried on a 3" by 2" wooden frame on PVC drainpipe posts. Thus far we are OK. The question then becomes, once we have the deck built do we simply paint it as one would do a 'deck' or should it be felted like a shed roof. The climate here tends to be warm and humid in summer with about 46" a rain scattered evenly through the year. My concern about felt is that it will trap moisture and promote rot.
Thoughts appreciated,
Peter in VA
Re: Working with Concrete Block
Posted: Tue Mar 26, 2019 7:56 am
by pandsrowe
Never actually having experienced the sort of climate that you enjoy (?), my observations are purely based on the experiences of others that seem to point towards your own feelings. I can understand that some think the extra protection of felt will help in keeping the eccesses of the weather at bay but my own view is that ease of drying out by allowing air to circulate is more important in these cases. Just think for a moment about a fence post in the ground, always rots where the moisture is trapped below ground but never above ground where the post can dry out.
Re: Working with Concrete Block
Posted: Tue Mar 26, 2019 1:25 pm
by BorisSpencer
+1 for the above comment.
Also consider that shed roofs are rarely flat, they are designed to drain.
The most important requirement is to eleminate places where moisture can sit.
On my own railway, which is all built from second-hand decking boards, I am still in a quandry over whether to ballast or not. I am worried that the ballast will hold moisture against the wood, especialy if glued in place.
To Felt or not to Felt
Posted: Tue Mar 26, 2019 1:53 pm
by IrishPeter
I am leaning towards giving it a good lathering with fence stain, rather than felting. The worry with our relatively damp climate is that the rot will set in quite quickly and I will end up with a bench life of less than 10 years. I do know that the decking boards are intended for use laid flat, and that the 10-15 year lifespan is calculated on the basis of being used that way with regular staining or painting.
Cheers,
Peter in VA
Re: Working with Concrete Block
Posted: Wed Apr 03, 2019 2:32 pm
by IrishPeter
The wife banned 'the brown stuff' as she did not want to be down wind of something that smelt like a garage, so I ended up using what they refer to as "deck stain" which seems to be some sort of paint. She is fairly sensitive to the smell of paint, varnish, etc., so I have learnt to be cautious as to which solvents I use around the house. Anyway, the deck stain soaks in fairly well, so I hope it will 'stick' unlike most modern paints which seem to more or less sit on the surface as a coating, and then curl up and die after a few seasons of mother nature. That said they seem to be a little less prone to that than they were 10-15 years ago.
I couldn't work out the reasoning behind the creosote ban except on the basis of protecting idiots from the consequences of the their own stupidity. The cancer risk, as I remember was pretty low, and I think those of us who used it with any regularity knew that like a lot of 'industrial' substances it was a case of wear gloves, old clothes and eye protection if you are messy painter - oh, and don't drink it, and don't bathe in it! For those of us who did not have a nanny growing up, H&S can be quite irritating.
Cheers,
Peter in Va
Re: Working with Concrete Block
Posted: Thu Apr 04, 2019 4:34 pm
by IanC
IrishPeter wrote: ↑Wed Apr 03, 2019 2:32 pm
For those of us who did not have a nanny growing up, H&S can be quite irritating.
Cheers,
Peter in Va
Indeed!
![:thumbup: :thumbup:](./images/smilies/thumbsup.gif)
Re: Working with Concrete Block
Posted: Sat Apr 06, 2019 8:46 am
by FWLR
IanC wrote: ↑Thu Apr 04, 2019 4:34 pm
IrishPeter wrote: ↑Wed Apr 03, 2019 2:32 pm
For those of us who did not have a nanny growing up, H&S can be quite irritating.
Cheers,
Peter in Va
Indeed!
What........
![:scratch: :scratch:](./images/smilies/icon_scratch.gif)
Re: Working with Concrete Block
Posted: Sat Apr 06, 2019 9:00 am
by FWLR
Hi Peter, I have made my line has described by most members with the plastic downpipes and wooden decking. It is easy and cheap. I put my downpipes at least 8" down , but didn't concrete them or put any inside the pipes, for the simple reason, because we rent any permanent fixing would be a nightmare to remove if we needed to move, just like we had to last year. Renting can be fickle...
I found though that they where sturdy enough and there was now question of movement, but then it is in that horrible clay stuff we have around here. If it was more soil based I think a more substantial mode of fixing would be needed possibly. I have put shed paint on the board and depending on what make you get, there is some really horrible stuff out there, thin and nasty, the stuff I used was ok but I have had to redo it, but I guess that's par for the course anyway. The Creosote is the better way to go, Anne is also very wary of any glues or paints that are strong smelling, so has COPD. So I tend to do anything when she is around.
When I was younger, my Father made those wooden fence panels and he sprayed them with Creosote and I can tell you from experience, it sure does sting your eyes....
Good luck with your build Peter, and let us have some photos of your'e building of the line please.
Re: Working with Concrete Block
Posted: Sat Apr 06, 2019 2:18 pm
by IrishPeter
Rod,
I discovered that we go to clay about a foot below the surface so I could have driven longer piles/post down into the clay, and not have concreted for five of the eight legs that hold up the decking. The other three would have had to be concreted thanks to their location being in the roots of a long since deceased tree, where there was a lot of soil, and decayed wood.
FWIW, I have a construction thread running over on the 'Railways & Layouts' - "Far End Tramway - Construction Starts." It seems to be coming along OK. The current design issue is how to deal with the station throat, and the transition to ground level running.
Cheers,
Peter in VA
Re: Working with Concrete Block
Posted: Sat Apr 06, 2019 2:33 pm
by philipy
IrishPeter wrote: ↑Sat Apr 06, 2019 2:18 pm
The current design issue is how to deal with the station throat, and the transition to ground level running.
Peter,
I had a similar quandry where my ground level line took off on to raised decking boards. The ground level section being 6" x 6" of poured concrete with a lot of ballast in it, which made it almost impossible to accurately drill holes in. I solved it by mortaring a couple of bricks to the end of the slab and then rawlbolting a piece of ali angle to the face of the bricks to act as a bracket to take the boards at the correct depth and give a level top surface. It's been there with no probs for about 5 years now.