Thursday, August 4, 2016
Building your home on sand
This was of course one of the issues when Jean and I purchased a residential plot on a sand dune!
As my work has included building works since around 1963 or so, plus four years at the Liverpool College of Building, I had been taught the options to a degree. Normal soil well drained and safe from rivers and earth quakes will probably be the plot of choice, oddly enough sand may be the next on the list, while clay will be the last choice.
http://www.blogspot.com/2009/02/tysons-of-5-dryden-streetliverpool.html
Its all about expansion and then contraction, a decent earth plot is stable and will not shrink or move much, the sand will not move either and as long as its safe from wash aways and floods is super stable. Clay is liable to shrink and crack in hot summer months, the cracks will also crack the building it supports?
http://www.blogspot.com/2008/04/certified-institute-of-carpenters-now.html
Jean with Janet who will have been around nine months old then.
Once the McBride residence plot was cleared, we left it to settle some while, it also rained more of less none stop for forty days (honest) that helped the issue of course and the sand settled rather well.
The sale of the land included a Beacon Certificate from H.M Shaw,Robinson & Case, the cost was R300, they did not check the becon positions, only that they were in place, my own survey with a hand bearing compass prooved three were in the correct place and that one was out by 1.5 meters, so its worth the effort to check them yourself.
In May 1983 I did the house design and drew the plans myself, they went through council ok but there was an ask that a structural engineer do stablity tests on the sand. In August 1983 Kantey and Templer were hired to do the test ( R168.90 back then) this was done at four points on the sand, inwards of each corner. The test rig dropped a weight or pile into the sand, readings of penetration were recorded and the readings were close enough to each other to get a pass mark.
Sand of course does have a nice feature, its very easy to dig out and the foundations were marked and dug out very quickly, the concrete was cast, the size was 750mm x 250mm and Pier, the master builder, who also constructed the North outer wall at the Hout Bay Harbour, placed some R12 reinforcing steel at the bottom of the concrete to add strength (placed up 75mm I think)
The ground floor is complete, the ceiling/floor has been placed onto laminated pine beams, note the roof trusses in the top deck.
The brickwork was by todays standards 'Green' as the bricks were made from recycled ash left over from the burning of coal at the now demolished Cape Town Power Station near Paarden Eiland, green was not an issue back then but by todays standards we would get an award for such use?
The garage was the last to be built, today I would do that first! Note piles of bricks and Builders Sand, you can not use the local dune sand, it must be sharp river sand.
House painting was done by John, Jeans nefew, he needed a dress blazer for the Camps Bay High annual dance, the painting paid for that.
Building on sand was fine, it just would be nice to have some nice green grass.
Burnt ash when mixed with cement is also very stable and while some 30 plus years later we did see some cracks in the brickwork, it was never a structural thing and I was able to fix them with great success using our 816 epoxy, 3M micro balloons and fumed silica, mixed together they make a perfect filler paste thats easy to use, it does not slump or shrink either.
The grass arrived with a large truck and was then rolled out on the sand, its still growing but does take a lot of water to keep it alive in the summer heat.
Building on sand, why not?
We did!
Roy
Time moved on, we stayed, did our maintainance, the girls married and moved out, we did more maintainance and still do so.
Yes, the same home built on sand thirty years back, the house is sound and the sands still there! The council planted the trees, named New Zealand Christmas Trees as they flower at that time each December, red flowers everywhere.
The home has been upgraded over the years, note the solar panels, last years addition when the six year old geyser started to leak. Eskom paid us a very nice rebate for the installation.
Druma our dog looks very content on what is a green lawn, the pavers went down some years back when a summer drought killed of the grass.
As my work has included building works since around 1963 or so, plus four years at the Liverpool College of Building, I had been taught the options to a degree. Normal soil well drained and safe from rivers and earth quakes will probably be the plot of choice, oddly enough sand may be the next on the list, while clay will be the last choice.
http://www.blogspot.com/2009/02/tysons-of-5-dryden-streetliverpool.html
Its all about expansion and then contraction, a decent earth plot is stable and will not shrink or move much, the sand will not move either and as long as its safe from wash aways and floods is super stable. Clay is liable to shrink and crack in hot summer months, the cracks will also crack the building it supports?
http://www.blogspot.com/2008/04/certified-institute-of-carpenters-now.html
Jean with Janet who will have been around nine months old then.
Once the McBride residence plot was cleared, we left it to settle some while, it also rained more of less none stop for forty days (honest) that helped the issue of course and the sand settled rather well.
The sale of the land included a Beacon Certificate from H.M Shaw,Robinson & Case, the cost was R300, they did not check the becon positions, only that they were in place, my own survey with a hand bearing compass prooved three were in the correct place and that one was out by 1.5 meters, so its worth the effort to check them yourself.
With the foundations cast, the next phase was laying of the brickwork.
Yes, we can walk to the harbour, we have our own sandy beach too!
The ground floor is complete, the ceiling/floor has been placed onto laminated pine beams, note the roof trusses in the top deck.
We now have a house, I just had to finish it, all works to this stage had been carried out by contractors.
The garage was the last to be built, today I would do that first! Note piles of bricks and Builders Sand, you can not use the local dune sand, it must be sharp river sand.
House painting was done by John, Jeans nefew, he needed a dress blazer for the Camps Bay High annual dance, the painting paid for that.
Note that peg or post near the road, thats the survey peg that was positioned wrongly, it should be 1.5 meters further out, so in the road!
Building on sand was fine, it just would be nice to have some nice green grass.
Burnt ash when mixed with cement is also very stable and while some 30 plus years later we did see some cracks in the brickwork, it was never a structural thing and I was able to fix them with great success using our 816 epoxy, 3M micro balloons and fumed silica, mixed together they make a perfect filler paste thats easy to use, it does not slump or shrink either.
You can see that while Janet has grown from the time we cleared the plot, she is still quite small, we took only a few months from start to finish before we moved in, Lorna too.
The grass arrived with a large truck and was then rolled out on the sand, its still growing but does take a lot of water to keep it alive in the summer heat.
Building on sand, why not?
We did!
Roy
Time moved on, we stayed, did our maintainance, the girls married and moved out, we did more maintainance and still do so.
Yes, the same home built on sand thirty years back, the house is sound and the sands still there! The council planted the trees, named New Zealand Christmas Trees as they flower at that time each December, red flowers everywhere.
The home has been upgraded over the years, note the solar panels, last years addition when the six year old geyser started to leak. Eskom paid us a very nice rebate for the installation.
Druma our dog looks very content on what is a green lawn, the pavers went down some years back when a summer drought killed of the grass.
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