House Foundation: The Braid

This is what the contractor calls ‘The Braid’.  It’s concrete reinforcement steel or rebar as it’s often called, at least in the US.  It took five men nearly two days to complete the structure, and the picture above is after the first day.  You can see the special pieces here designed to fit into the inkassing.  You can also see the piles have been filled with concrete and also have steel reinforcements coming out of the tops.

Below is a picture of the same part of the wall, but from more of a distance.  This picture was also taken the second day after they finished.  You can see it’s been built up in layers and in many places, especially connecting the rows of piles, you can see extra reinforcing material was added to give strength in specific places.  This was all very carefully and mathematically planned by the construction engineer.

This last picture is almost the same as the previous, but you can see the extra lines of reinforcement a little better.

Tomorrow the concrete will be poured, and what’s called the construction floor will be made.  After this happens our house will have it’s new foundation and will finally be stabilized!  In total the construction floor will be about a foot or 30cm thick, and on top of that we’ll put a layer of insulation, floor heating and finally a finished tile floor.

Until now we’ve been enjoying walking around in the space with it’s high ceilings, and it’ll be a shame to lose the extra height to the thick floor.  We will actually gain about a foot (30cm) of height compared with what was there before, but to put the new floor in deeper than that would have been too expensive, because it would have meant working under the water table.

The other thing that’s critical about this stage of the project is that once the concrete is poured into the inkassing it can never be undone, so tomorrow when they pour the concrete it will be an irreversible step.

Uncovered History

These are two pieces of ceramics I came across in the last month.  It’s funny, I don’t think I’ve ever come across old ceramics here in the ground, so twice in one month is all that much more unusual.

On the top is by far the most special find.  This was found by the contractor working on my house foundation, and it’s a 300+ year old piece of Makkumer tile, made by the oldest still operating business in the country, Koninklijke Tichelaar Makkum. It’s also still a family business, passed on from one generation to the next.  This will be the last generation however, because the current generation of children have other interests.

The piece of ceramic below, I don’t know much about other than it appears to be part of a lid to something, because underneath is a lip to hold it in place.  I doubt it’s more than 100 years old, but I don’t know.  I found it while digging in my community garden.  The previous gardener had built a foundation for a greenhouse by driving fence posts deep into the ground, and in the course of removing them I had to dig a very deep hole.  I found this piece of ceramic about one meter deep.

It’s really quite a vivid blue color for being so old, and it makes me wonder a bit what kind of very toxic chemicals may be in the glaze.  Anyone have any idea?  Cobolt maybe?  We were just discussing this kind of thing here.

Inkassing

This is a Dutch word to describe what they are now doing on the foundation work.  If I look up the word in an online dictionary, it says ‘recess’, but I don’t think that’s quite right.  Anyone have a better translation?

Anyway, in the picture above, you can see they have made some holes in bottom of the wall, 50cm every 50cm to be exact.  They will make these holes all the way around the house, and in each one put a jack like you see above.  In this way, half the house will be supported by means of a jack.

In foundation repairs jacks are always used.  This is because you somehow have to move the weight of the house from the old foundation to the new one, and jacks are always needed in some way.  I think the way they will do it with my house is a little unusual however.

What will happen is they will pour a new concrete floor and entomb the jacks, as well as fill the spaces in the walls.  The concrete floor will have a complex reinforcing structure, and will be supported by the piles that were driven earlier.  The new foundation will then be in place, and capable of supporting the house.

Over time, the old foundation will continue to degrade and sink, and in this way the weight will gradually be taken up by the new foundation.  The construction engineer mentioned he included in his calculations that the old foundation will continue to provide a degree of support for the house into the future.

Murky Depths

It’s been a while since I’ve posted anything about my house foundation, with all the excitement of the events in Brussels, I almost stopped paying attention.  They’ve just gotten to the exciting part!  They’re removing the contaminated ground under the house.

Since the house is built nearly at water level, they didn’t have to dig far before they reached water.  In the picture above you can see they inserted a measuring stick so they could monitor the water level with respect to the dirt.  Soon they are going to start running a pump to remove some of the water, so they can dig deeper.  Rain is forecast, so the water table might start rising too.

You can see the pipes sticking out of the ground are what they drove for the piles.  They aren’t yet filled with concrete, but that’s due to happen on Monday.

The smell is quite incredible.  Oily and very dirty smelling.  It’s classified by the city as very toxic waste (when compared to what they usually find under peoples houses in the city).  Mostly it’s heavy metals that are the problem; high levels of zinc, a bit of lead and mercury, and some other things.  The test showed traces of petroleum distillates.  It’s very dirty!

According to city records, until 1930 or so the house had a dirt floor.  What they found was 3 different concrete floors built on top of one another.

The house is 350 years old and and been sinking the whole time.  Literally, from one generation to the next, they’ve just been dumping their crap into the floor, letting it sink and building a new floor on top.

Here you can see the former load bearing wall I posted about before.  Now it’s a nice new steel beam.

Bricks!

They’ve made remarkable progress over the last few days.  The wall is almost gone, just a few difficult spots left.  They’ve also broken up half the floor.

Where the wall used to be are piles of bricks…

There’s an incredible diversity among the bricks.