Lifespan of slats?

Muckit

What is the lifespan of slats?

Reason I ask is I noticed a crack running top to bottom on the gable end wall of the slatted shed. The wall is 6" block on the flat. The wall is built over the slats (pens one side, agitation point outside). Shed built ~1998. Cattle are ran along agitation slat to crush, so would be pressure on this wall from outside from time to time.

Obviously some movement has occurred somewhere... either gone down or in or out. I'm hoping that the slat hasn't failed and that it's from the cattle pushing in or out.

Any thoughts??

grumpyfarmer

We had to replace the gangs in our slated house,build in 1979, in 2007 as all the concrete started to flake off the bottom of them up to the steel..

vanderbadger

Muckit wrote: »

What is the lifespan of slats?

Reason I ask is I noticed a crack running top to bottom on the gable end wall of the slatted shed. The wall is 6" block on the flat. The wall is built over the slats (pens one side, agitation point outside). Shed built ~1998. Cattle are ran along agitation slat to crush, so would be pressure on this wall from outside from time to time.

Obviously some movement has occurred somewhere... either gone down or in or out. I'm hoping that the slat hasn't failed and that it's from the cattle pushing in or out.

Any thoughts??

hard to say without seeing underneath them, had a look under some of our probably done in the early 80s there 3 or 4 years back..got a fright..all cracks and steel visable in spots..

pakalasa

20 Years - read that somewhere recently.

Muckit

Would most of ye have done similar and built gable wall straight over the slat? Have ye block or mass concrete?

F.D

best thing to do is have a look underneath as suggested, but be careful !
During the Grant Era a few years back would the slats have been made to a similar standard as the ones in the late 70/80's or could you expect to get longer out of them?
If 20 years is the lifespan, i'd hate to be after building one of those new slurry tanks with suspended cubicles and feed passages and having to replace all the slats in 20 years time that would be a huge cost

reilig

All the slats used during the grant era came with a 20 year guarantee. They should last a lot longer than this (40 years +) if they were the right spec

bbam

Ours was built with single Slats back in early 70's
There is no agitation point so each year we have to lift 6-8 slats to agitate and spread. Appart from one which has a corner off it they look perfect all way round, no cracks steel or rust.

I'd never thought of their lifespan much before. Do people only change if they have visable defects?

grumpyfarmer

Muckit wrote: »

Would most of ye have done similar and built gable wall straight over the slat? Have ye block or mass concrete?

Yea a block wall in ours

Muckit

bbam wrote: »

I'd never thought of their lifespan much before. Do people only change if they have visable defects?

I wonder has anyone got caught out? This would be my, and I'd say any farmers, worse nightmare.......... head out and see a pen of cattle down in the tank :eek:

You would hope that you'd see visible crumbling instead of a sudden failure....

Muckit

Muckit wrote: »

Would most of ye have done similar and built gable wall straight over the slat? Have ye block or mass concrete?

It seems this question is in the same league as... 'how many cattle have you?'

pakalasa

http://www.teagasc.ie/newsletters/safety/saggingslats.asp

jimmy G M

Muckit wrote: »

Would most of ye have done similar and built gable wall straight over the slat? Have ye block or mass concrete?

Yeah block wall built straight on the slats. 1989. Slats appear to be in good nick. Harrington slat as far as I remember.

Farmer Pudsey

Muckit wrote: »

I wonder has anyone got caught out? This would be my, and I'd say any farmers, worse nightmare.......... head out and see a pen of cattle down in the tank :eek:

You would hope that you'd see visible crumbling instead of a sudden failure....

Heard a story last year of a farmer that had cull cows on slats 9 or ten in the pen, looked in, taught it a bit empty from a distance, 4 in the tank saved some got a few lads with tanks to empty it fast but still lost two I think. The cows above were looking down at the ones below. I think that some single slats collapsed togeather

babybrian

happened to us a few years ago, it was two doubles that had been cut because back in the day of 1981 there was no half gangs so had to cut full gangs but this exposed the steel to the air and down it went and 4 incalf heifers along with it. There was about 3 foot of slurry in the tank, my dad went in with a rope, 1 by 1 tied their heads to a neighbours front loader at the agitation point and up they came, shaken but ok, all calved few months later no problems. slats replaced now including the gangs.

I luckily missed all this as I was sunning myself in Australia. Looking back now he shouldnt have went in to the tank(gas) and if it ever happens again I think I would be calling the fire brigade.

Vandy West

If block wall is built parallel to the span of the slat (on top of one slat) then slat probably sagged.
If there are multiple slats crossing under the wall, and there is no tank wall (or beam spanning ope to agitation point) then the problem is probably the slats sagging.
If there are multiple slats crossing under the wall, and there is a tank wall (or beam spanning ope to agitation point) then the problem is most likely not the slats.
What is the height of the wall? width between columns? Is the wall run into the web of the column or just butted up to the column?
Since crack is vertical sounds like the wall support has sagged, If it got a knock from an animal the crack would probably be partly horizontal.

jimmy G M

Vandy West wrote: »

If block wall is built parallel to the span of the slat (on top of one slat) then slat probably sagged.
If there are multiple slats crossing under the wall, and there is no tank wall (or beam spanning ope to agitation point) then the problem is probably the slats sagging.
If there are multiple slats crossing under the wall, and there is a tank wall (or beam spanning ope to agitation point) then the problem is most likely not the slats.
What is the height of the wall? width between columns? Is the wall run into the web of the column or just butted up to the column?
Since crack is vertical sounds like the wall support has sagged, If it got a knock from an animal the crack would probably be partly horizontal.

Maybe Muckit can put up a pic?

mikeoh

it ever happens again I think I would be calling the fire brigade.[/Quote]
Out of interest do u think would they come?......I think there is no services in Ireland for animal rescue.

Dont be daft

mikeoh wrote: »

Out of interest do u think would they come?......I think there is no services in Ireland for animal rescue.

After what happened in the North I'd say they'd come.

Wouldn't like to see the bill they'd send out after though. I'd presume farm insurance would cover this but I don't know.

On the topic of slats we've slats put down in 1977 and they seem fine. They were inspected in 2008 as we were going to plough the grant into them but I'm told they were grand.
I'd say a lot of it is down to the quality on the 1st day. Have heard of 20year old slats giving way.
I'd say the modern slats would be good for 40+years.

Muckit

jimmy G M wrote: »

Maybe Muckit can put up a pic?

At the weekend if I get a chance. The wall is not on a full gang slat. I think it's 2 slats of a full gang. The idea at the time I think was to put this half bit under the wall to make it easier to change the rest of the slats when the time came.

Looks like the wall will be coming down and a new slat piece slotted in this summer.. If the slat hasn't failed, I'd just brace the wall some way

MfMan

Inspection of slats even when tanks are empty (i.e. during summer) can still be dangerous as noxious vapours can still be present in the bottom of the tank. All precautions taken should be encouraged. BTW, what happens if a slat with rubber on it has to be replaced? Does the rubber have to go also?

pakalasa

Concrete is about 10 times stronger in compression than in tension. When slats are loaded with heavy cattle. The under side is in tension and the upper surface in compression. That's why the under side always flakes away first. So you really can't tell how bad the problem is until you look at the under side. That , as we know, isn't the easiest thing to do.

Figerty

I got insurance last year on slat collapsing,. Ony €20 or so with FBD. It's the only 'luxury' insurance I have taken out.
For older slats I would reccomend it. Mine are only five years old, but I have taken the view that this could happen anytime.

Muckit

Location of crack. Cubicle bed to right.


Pic of crack on outside this evening


Crack on inside




Here you can see the cut slat wall is built on

pakalasa

Muckit, that doesn't look good. How many slats in the gang slat supporting the block wall?
Can you put a straight edge on top of the slat to see if it is sagging? It would want to be nearly as long as the slat itself.

moy83

Thats a dirty one muckit . Is knocking the wall and replacing the slat your only option ?
If you thought the slat wasnt too bad could you take the weight off it by knocking the wall and replacing it with barriers and maybe stock board ?

Bizzum

MfMan wrote: »

BTW, what happens if a slat with rubber on it has to be replaced? Does the rubber have to go also?

The easi-fix mats can easily enough be replaced on the slat. You'd whip them up in a few mins where they're not screwed down but those screwed down or around the edges where flat mats are screw fixed it might be a bit trickier but probably do-able!

caseman

Is the crack about 1foot from edge of tank thats how it looks from the photo.
If so i would not be worried , ground between tank and back of shed has sunk whick caused crack.

Bizzum

pakalasa wrote: »

Muckit, that doesn't look good. How many slats in the gang slat supporting the block wall?
Can you put a straight edge on top of the slat to see if it is sagging? It would want to be nearly as long as the slat itself.

I dont like the look of it either. I'm wondering this: If the slats sagged, presumably somewhere near the middle of the span, would the crack not be widest at the bottom of the wall? ie. at ground level?

Muckit

caseman wrote: »

Is the crack about 1foot from edge of tank thats how it looks from the photo.
If so i would not be worried , ground between tank and back of shed has sunk whick caused crack.

@Caseman..
Ya I freaked when I spotted it last weekend, but looking at it again today in the light both inside and out, I think it has more to do with the wall being built on both slat and strip foundation (outside cubicle).

@Bizzum...
yes I thought this strange too that the crack is bigger at the top. Surely it would be bigger at bottom if slat was sagging?

@Pakalasa...
The slat looks in no way sagging. If you look at last pic, you can see that wall is not on a full gang (note break)

Muckit

I will be taking a good look underneath once tanks are emptied.

Thinking logically about it, I don't see that slat going anywhere. I can't see a sudden fail of either wall or slat. As you said bizzum, if wall was moving down in middle, wouldn't crack be bigger at bottom??

What also eases my fears is that cattle are not standing on the same slat as the one supporting the wall.

Bizzum

I suppose it would be prudent at this stage now to measure and record the extent of the crack so as to be able to see if it's getting worse. Time to tape over the crack!

jimmy G M

caseman wrote: »

Is the crack about 1foot from edge of tank thats how it looks from the photo.
If so i would not be worried , ground between tank and back of shed has sunk whick caused crack.

This likely the case given the crack is wider at the top than the bottom, & muckit says the slat is not sagging.

If so then the question moves on to how to strengthen the wall so it wont fall out. My suggestion here is to make up a metal post (or 2) which sits on the slats with a leg/extension going down each side of the slat to stabilise it. Then brace to the wall with a couple of lengths of steel inside & outside the wall.

Sorry prob not a very clear explanation.

jimmy G M

Tidy looking yard by the way muckit

Good loser

Muckit wrote: »

I will be taking a good look underneath once tanks are emptied.

Thinking logically about it, I don't see that slat going anywhere. I can't see a sudden fail of either wall or slat. As you said bizzum, if wall was moving down in middle, wouldn't crack be bigger at bottom??

What also eases my fears is that cattle are not standing on the same slat as the one supporting the wall.

There isn't much to worry about - for 20 years anyway.

Could bolt a 3 ft length of 3 inch angle to middle of inside end wall of tank with another 12" to 15" piece projecting at right angles supporting the slat/wall. Basically an L shaped piece of 3" angle turned upside down.

Muckit

jimmy G M wrote: »

Tidy looking yard by the way muckit

Thanks. That was taken during the summer a week after powerwashing, not quite so clean now!

Figerty

Good loser wrote: »

There isn't much to worry about - for 20 years anyway.

Could bolt a 3 ft length of 3 inch angle to middle of inside end wall of tank with another 12" to 15" piece projecting at right angles supporting the slat/wall. Basically an L shaped piece of 3" angle turned upside down.

I would agree with the suggestion. Put a strap along the top of the wall in case it moves.
I have a similar crack on my walls i linke with where the wall above the tank meets the back of the shed. Differential settlement so I am not worried about it.
I would put piece if channel iron on the flat on the top about 8 -10ft long on the top of the wall and rawl bolt it down about every 9 inches. It might slow down a collapse but i don't think that will happpen anyway.
You have an aggitation point near that crack, I'd hazard a guess that the vibration from the aggitation caused the crack to grow.