String Theory

The last two days has been all about laying out little orange strings that indicate the outside edges of my footing.  I had these dimensions identified by survey, instead of the actual foundation dimensions, to aid in the excavation.  Once in place, I will measure off these lines to identify the edges of the foundation.

Ted, a friend and fellow home inspector,  dropped by yesterday afternoon and this morning to give me a hand.  It has been great to have the assistance, company, and to have someone to bounce solutions off of when problems crop up.

I started yesterday off trying to drive wood stakes into the ground.  I tried driving a metal stake first to create a pilot hole and also rented a jackhammer to try to make a pilot hole but nothing worked.  The wood stake would just bounce out of the very dense sandy clay.  The jackhammer was the worst option as it would partially liquefy the soil meaning it would just cave back in when removed.  I finally had to go out and rent metal curb/form stakes which are 2′ long 3/4″ metal stakes with holes drilled through that allow you to attach lumber to them.  I was able to drive these in all the way leaving the last 6″ or so and then screw a wood stake to them to provide the above grade portion of the batter board structure.  Along with cross bracing, I now had sturdy batter boards ready for running string lines.

With this hurtle solved, I moved on to transferring the footing lines from the strings at the top of the pit down to the bottom using plumb bobs. Ever noticed how the hole in a plumb bob makes it impossible to thread a string through.  It is JUST wide enough for the string, but trying to push a string through is next to impossible.  So, I just drill out by one size bigger and save myself literally hours of work.  With Ted’s help, we moved 3 of the more major lines down to the pit floor yesterday.

This morning started off with a bit too much water in part of the pit again.  Turned out a power chord had slipped and fallen into the water where it blew the GFCI.  With the 2.5″ of rain we had last night, it did not take long to build up a foot or so of water on the north half of the pit.  This was a fast fix and within a couple of hours the pit floor was generally dry again.  I also had the shed cam go down at some point yesterday evening which turned out to be water travelling down the LAN chord into the connection.  This too was a fast fix.

Once Ted arrived,  we picked up where we left off yesterday and started to check the dimensions from the north side of the house to the south.  We were off between 1.5″ – 2.25″.  Not good!  So the next hour or so was spent to try and figure out what had shifted.  In the end, we could not find a logical reason.  All of the batter boards originally surveyed could not have moved enough to account for this variance so they may have been off themselves.

In the end, I analyzed the best line to pick as our starting point and then worked off it to true up everything else.  My ancient memories of geometry were put to good use as we employed the Pythagorean theorem to ensure our perpendicular lines were square to each other.  I had a bit of a hiccup when I decided to work backwards from the hypotenuse and one leg, but after a few minutes I gave up on trying to work the problem from that angle (scuse the pun), and worked instead from two legs and of course this time it was fine. It was only after I left the site that realized I was adding the two instead of taking the leg away from the hypotenuse.

By 1 PM, we had laid out all of the lines that can be done before I need to move some dirt out of the way with the tractor.  I had med appointments in the afternoon, so this closed down our day.

Tomorrow I will do a tractor repair (we discovered today a fan belt was shredded) and will start moving the final dirt.  I also hope to lay out the final batter board and then start laying out the internal footings.

It feels good to finally be progressing on actual construction.  Ted has been coming by because he wants to see the footings done and behind me.  He has generally been propagating a ‘lets get her done’ attitude.  But after working with me today, understands the very tight space tolerances of this site as well as the special consideration needed for an ICF foundation, and how rushing through this is not an option.

As I will be pouring the first row of ICF with my footings, it is essential that the layout is as accurate as possible and does make footing layout more crucial than normal construction.  My dwelling is very close to the front yard setback (within an inch), and I have minimal room between the foundation and the concrete blocks at the NW corner of the pit.  I also have very little room between the basement walkout foundation and the concrete lock blocks.  So even an inch can make a monumental difference in some of these tight spots.  I will therefore continue laying out with enough patience to ensure we get the strings where they need to be.

Thanks for visiting.

 

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