Gable-ends & drains

More destruction

As agreed with the architect, we demolished the gable-end wall with no foundations at one end. It faces north, overlooking our driveway and the shared access track.

We put two bays of scaffolding, 2 tiers high, across the front, giving us a top platform just the right height to remove the top-most capping stones. I put boards at convenient levels to lug all but the largest stones down. I used the chain hoist and webbing straps for the really big ones. Smaller bits of stone I chucked off the side and periodically barrowed to a pile the other side of our driveway.

At the top of the wall, I made slow progress because the chain hoist was very slow to use, however the mortar broke apart easily – our pry-bar was more than equal to the job. As I worked down, the hoisting got quicker, but the mortar was progressively harder. I stopped once we were below wallhead height, I would have needed to use a breaker to carry on down and Ric could finish the job with the digger. I worked the wall back towards the west corner, allowing room for the garage door and quoin stones. I did clear the unsupported stonework on the east side right down to ground. It was overhanging part of our drains and at several points I used a length of rope to hold stones in place to stop it all collapsing.

I have no headfor heights, this is about my limit!

First we got the capping stones down and put to one side.

We used the chain hoist to get the nig stones down.

Slow old work, getting this far took more than a day.

I put the stones to one side – a pile of big ‘uns and a pile of little ‘uns.

The area over the excavated foundation more or less took itself down!foundations

This doen enough to let Ric get in with the digger.

And the job is about finished.

The soakaway: Our surface water soakaway needs to hold 16 cubic meters of rubble, to give around 4 cubic metres of free space. This is what the standard calculation says we need, to cope with our 200+ square metres of roof plus a steady flow from our diverted field drains. Our high water table meant it would be a 4m x 4m x 1.3m deep hole in the ground near our southern boundary, allowing for 30cm cover.

The hole was scarily large, we cleared suitable lumps of ready broken concrete from across the site but ran out, with what looked like a puny pile in one corner of the hole. We moved over to our big concrete pile and scavenged all the bits of easily-breakable hardstanding that George had piled up there. I did duty with the sledge hammer to break them to size. We could have used the hundreds of tonnes of large blocks of concrete, but it was much harder and more thankless work. We started with wheelbarrows to get the rubble to the soakaway but were relieved to get hold of the 1-tonne mini dumper truck – life immediately became a little more attractive. The hole was rather more than half-filled before we ran out of easy stuff to break. Ric took pity on us and lifted fresh hardstanding in the courtyard, which lasted us almost to the finish. We foraged further onto the concrete pile for the last three dumper-loads.

It was a miserable job, over four working days – with lighter work to break it up. Ric had worked in parallel on the drain to the soakaway and ran brown pipe into the middle of the rubble, 30cm below the final level. We spent a while getting a level surface to the rubble and it was done.

It was remarkably effective. Being somewhat jagged, the broken concrete locked together with plenty of open space, yet was firm enough to drive the loaded dumper onto. We ordered weed membrane to go on top, Ric will finish it off with subsoil and then topsoil after we have headed south.

We used upmost of our easily-breakable concrete.

Fortunately we had mechanical assistance.

Here is the surface water drain running into the soakaway.

Ready for geotextile & soil to cover.

Surface drains ‘getting there’: Ric dug the drain trench back up the plot from the soakaway, to the junction he had buried last year. He put an inspection chamber in, not far from the soakaway, so that we can monitor how the whole thing performs. He broke two holes into the big concrete tank, to run brown pipe downstream and upstream. We used pea gravel to lay and level the pipes, topped them with gravel and filled the trenches. A neat operation that took around a day, plus time to cement the drain pipes into the tank.

We have a near-complete surface water drain. We are missing two extensions into the courtyard and a bit that we cannot do until we divert our field drain.

The end of teh surface water drain.

The drain heads back upto an inspection chamber.

Then up to the big concrete tank.

Here is where it goes into the tank.

What Ric did

The field drain: Ric pressed on with sorting out our flooded driveway area. He discovered where the field drain we found last year, at  the bottom of our south-west corner foundations, runs once it clears the building. Having scraped away the soft topsoil, he could see a clear run of softer ground. It runs parallel to the west wall of the steading and appears just about where we had put our mail drop box. It carries on in a straight line under the shared track and into our neighbour’s field. We had already agreed with the architect that we would divert it into our drains. Given the levels, we would need to break into the drain on the neighbour’s side, to get enough height to run it into our rather higher-level surface water drain. We will need to dig across the shared track. I got the blessing of Mr Aitken to do this, at a date to be agreed.

Cause of flooding driveway identified?: We decided to run a french drain across our flooded area, towards the corner of our plot to where we had previously seen standing water. Whilst digging the drain, Ric discovered what we hope was the cause of the whole mess.

It seems that in 2015, when the contractor ran our water supply across the shared track and up to our steading wall, they cut across some near-surface field drains running west-east. The damaged drains blocked when that trench was filled,  had ponded up water and has been seeping water ever since into our driveway. Indirectly, this would also explain why, when we bought the property, we though we heard running water round about the wall of the steading that will have our garage door in it, but have not heard it for the last year or so. We never worked out why water was running, but we noticed when it stopped.

We also found out that the contractor had dumped turf and soft soil at the bottom of the trench. Ric sorted that out.

He included a length of slotted drain pipe in the French drain and connected it into the surface water drain. He left the far end of the drain trench open, in case we want to extend it further. It initially had standing water in the bottom, but dried up after a couple of days – hopeful sign.

Fixing our driveway off the track: Our 20 tonnes of MOT Type 1 (sub-base in the vernacular) arrived, Ric got it laid and rollered and we have a good driveway on and off the track. There is no soft ground so far and plenty of room for most trucks to be able to back in and drive out forwards. We can do something about it in a year or two to run right up to our garage door and provide our additional parking spaces.

The sub base is to allow trucks on and off site. If teh levels are right we can extend it forwards to teh steading when we have the garage floor and drainage in place.

Wall problems: In sorting out our driveway, Ric had cleared away surface soil right up to the steading wall. He looked more closely and made a disturbing discovery. The north-west gable-end wall that overlooks the area has a large concrete trough against it which we needs to remove. At some time in the past, the entire wall foundation to the left of the trough had been dug out – there was nothing holding it up. The perpetrator had installed some sort of brick construction in the space, with short lengths of field drain running into it. We think that latter are the remains of the field drains damaged by the contractor who installed our water supply. We also think this was where we heard the sound of running water when we bought the property, although it was overgrown at the time.

Anyway, we did not even want to remove the concrete trough until we had decided how to make the wall safe. Ric got the architect in. The options were to very delicately underpin the wall in several operations, or to cut our losses and pull the wall down. The advantage of pulling down is that we can build the garage door into the new build rather than having to prop the wall and pull out the stonework. Caution won out, we will demolish most of the wall, put a foundation in and re-build. A bit of a blow, though.

The ground has been dug away underneath the wall.

Preparing for a concrete crusher: George claimed sometime last year that he knew someone with a portable crusher and that he would see if they will break our pile of concrete into hardcore. Given we are talking about laying the floor slab later this year, we nagged him until he did something about it. Ric cleared enough space to dump large amounts of crushed concrete.

A hidden surprise: Ric finished our driveway and headed round the back of the site to look at the surface water soakaway. He traced the line the drain would follow from where he left it last year. There was a concrete shed base in the way, so he got the breaker out and planned to break it up enough to use the digger on it. Except that it was not a shed base, but the reinforced concrete roof to a ginormous buried water tank, some 2m x 3m and over 2m deep. It is half-full of water, with sludge at the bottom. It has clay pipes going in and out and is a bit of a mystery at the moment.

Ric suggested cleaning it out and using it as a supply of water for the garden. He created an opening just about big enough to get a person in and plans to run the surface water drain in and out.

Ric tried to break what he thought twas a floor slab.

Once he realised what it was, he broke out this entrance hole,so we could maintain it.

More drain work: He went round the surface water system he installed last September, dug out the spare sockets he had put in but buried and formed the connections for our gutter downpipes – one on the north side at the east end, one each end on the east side and one on the west-most wall at the south end. He topped-up the ground along the entire length of the trench where it had settled over the winter. He got the level out and planned the run down to the soakaway. He found a point that would work – the drain needs to enter at 300mm depth, but the soakaway needs to be shallow enough to be above the water table. He then dug out the soakaway – 4m x 4m x 1.3m deep (1m deep of rubble, 30cm of cover).

At this point Ric had to head south to sort out a couple of problems, due back after a fortnight, at which point we would also be on site.