Preparing the slab #1 - My House Extension

A one storey extension
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Preparing the slab #1
Mains water feed: I need to cut off the 1/2 inch BSP water pipe and connect it to standard 22mm copper pipe.

The first task is to turn the mains water supply off on the pavement outside of the house with a specially bought 4 foot long stop-cock spanner.
Using an angle grinder with a metal blade I cut the pipe off.
I used a special compression adaptor bought from the local plumbing shop to convert it to 22mm pipe. The adaptor is made by: George Fischer Piping Systems.
I brought the mains water pipe straight up using a plastic pipe to protect the 22mm copper pipe as it passes through the 150 concrete slab.

No leaks!
Saturday, 21st April: I filled in the foundation trench within the wall with soil and rubble stamping it down as I went.

When ready the surface will be covered an inch of sand to ensure that the first DPC sheet is not punctured by rubble.

Notice I said "first" - The Building regulations Surveyor has said I should use two of three - more on this later.
It's really beginning to look like an extension now!
After a lot of thinking, I have decided to change the layout of the drains. The 40mm kitchen sink pipe now connects into the main house drain using an adaptor. This means I can do away with the external open drain. This is much tidier with the pipe eventually being covered by the step from the kitchen door.

The main drain will be taken through the 150mm slab but will be blocked underneath the screed so that it could be made available to use if so needed in the future.
I've also marked the bricks that need to be removed to key the slab into the wall using white paint. Taking out the vent in the middle of the wall showed me that the wall is solid and has no air gap. This will make it a little more difficult to remove bricks to a depth of 100mm as many of the bricks are laid lengthways across the width of the wall.
Inspection chamber cover:  As the drain inspection chamber is inside the extension a double sealed unit is required.

I ordered on-line a 450mm x 450mm doubled sealed and lockable cover from Manhole Covers Ltd. It's really nice to be able to on-line as many other building related product sites don't even list their retailers!

The part number was MHC-7123/DSL
This picture shows how the double seal works.
The cover only took two days to arrive after ordering it on-line from the supplier's web site.
Monday, 23rd April: This is the job that I was really not looking forward too!

However, I found that using a hired Kango masonry saw really made the job quite easy.

Remember, the wall was solid so I had to cut only half way through the wall!
I cut the first two slots in half an hour and I couldn't suppress my worries enough not to put bricks in the slots!
It only took me a couple of hours at the most to cut all five slots so it was a task that was much simpler than I actually thought.
Copyright: Chris Gare 2007 - 2018
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