Neat silage pit using wall panels

I recently featured a milking parlour made using precast wall panels. Here, I feature a silage pit also made using panels, showing their versatility. The pit is on the farm of Brian Reidy at Cahir, Co Tipperary.

He had one pit, but added a second one alongside it of the same size. Brian farms 50 sucker cows to stores and finishers, with the help of his father, Pat. Brian also works as a dairy and beef nutrition consultant. He sourced the panels for the pit from Alfabloc of Copeen, Co Cork.

Picture one

The new pit is 9m wide and 18m long (30ft x 60ft). The side and end walls are made of the precast panels. Brian’s pit wall is two panels high. Each panel is 1.2m (4ft), giving a wall height of 2.4m (8ft). Each panel is 4.5m (15ft) long.

Picture two

Panels are supported by rolled steel joist (RSJ) pillars. They can either sit into the web of the pillars or, as here, lean against one flange.

Lowering the panels into the web of pillars is a good option where there will be weight against the wall on either side, eg bulk materials such as feed or fertilizer. The two flanges support the panel against force from both sides.

Picture three

However, leaning the panels against one side of the pillars is the best option if you want a smooth, uninterrupted wall face for an easy, clean removal of all material and no snagging of front loaders, etc. There’s plenty of tyre marks on the walls of this pit, showing how the tractor can drive close to the wall.

Picture four

When panels are leaned against RSJs, they are clamped in place with bolt-on brackets, one at each corner. A threaded hole is precast into the panel to accept a bolt.

Picture five

Panels are grooved on the bottom and tongued on top. Here is where four panels meet.

As we can see, they sit very neatly together. There’s no daylight visible.

Picture six

This is the dividing wall between the old and new pit. As we can see, it’s a double wall – there are panels on each side of the steel pillar.

It’s possible to make a dividing wall using one set of panels, sitting them into the pillars.

If the panels and RSJ are well matched in size, then the two wall faces will be neat and good to work with.

Here, the right-hand wall was already in place as the side wall of the original pit, leaning against the steel RSJs.

When it came to making the new pit, Brian decided the best thing to do was to place a second wall of panels against the other side of the RSJs.

The steel pillars are not in contact with silage acid. It also gave two nice, smooth walls to work with.

Incidentally, the first panel wall had been built to replace a clay bank wall to give the pit more capacity.

In this picture, we can see the precast tongue and groove. We can also see the steel reinforcing wires that give strength to the panels.

These panels are 150mm wide and each has 12 reinforcing wires. The wires are put under tension in the moulds and the concrete poured in.

It is the wires that give the concrete panels their strength under loading. Because the panels are precast in factory conditions there is a high level of quality control.

Costs

Brian Reidy erected the walls of this pit himself, with the help of two neighbours. They dug out a hole for each RSJ, stood the pillars and backfilled with concrete. When the concrete was set, they borrowed a teleporter and put the panels in place against the pillars.

Alfabloc makes 100mm and 150mm panels, 1.2m high and up to 6m long. The 150mm panels are listed at €51/m length and the 100mm ones are €46/m, all plus VAT.

Brian Reidy told me that the panels for the new pit cost him €5,600, including VAT.