Planning the build
Why build an extension?
Initial design sketches
On-line Building Regs
Meeting planners
 Meeting building control
 Planning the foundations
 Planning the floor slab
 Marking out the footings
 Damp proof course issues
 Possible drainage problems?

 Construction of the walls
 Proposed roof structure
Windows diary
 Window challenges
 Initial window plans
 Making the casements
 Making the frame
 Designing leaded lights
 Making leaded lights
 Assembling the window
 The little window

 The door frame
Demolition diary
 The demolition starts!
 The demolition continues
 Still more demolition

Foundations diary
 Foundation issues
 Drain issues
 Digging the foundations
 Rethinking foundations!
 Pouring the foundations

Floor slab diary
 Rethinking the slab!
 Floor vent extensions
 Preparing the slab #1
 Preparing the slab #2
 Pouring the slab

Walls diary
 Preparing to build walls
 Build up to the DPC
 Build the walls #1
 Build the walls #2
 The gas men cometh
 Build the walls #3
 Finishing the walls
Roof diary
 Roof structure build
 Tiling the roof
 Finishing the roof
 Finishing the gables
 Roof insulation

 Floor screed
 Shower room
 Shower room floors
 Shower room walls
 Utility room
 Utility room walls
 Utility room floor
 Finishing the windows

Project finished!
 Final inspection
 The certificate
 Final thoughts

 Twelve months on!
 Material costs
Sister sites
 House re-roof project
 Home gas usage data

 Stop paint flaking
 DIY secondary glazing


Getting ready to pour the slab - #2

Tuesday, 24th April:

Reinforcement mesh: The Building Control Surveyor proposed that I should use B785 structural mesh steel reinforcement mesh so I will order two tomorrow from Jewson they are 3.6m by 2m in size.

Nearly there. The task for tomorrow is to smooth the site, cover it with a layer of sand, build the shuttering that will contain the slab and cut and place the steel mesh.

The mesh was delivered nice and early but boy were they heavy - each a two person lift!
An hour was spent flattening the soil and rubble.
Then I started the task of fitting the the mesh which involved a lot of cutting - I wouldn't use a hacksaw to do this job!
Eventually, the first mesh fitted OK. It was cut so that the mesh fitted inside of the slots cut in the house wall.
The second mesh sheet was a bit more challenging to fit and required a lot more cutting.
The mesh was then removed and a final layer of sand was laid to prevent the damp proof membrane (DPM) being damaged.
Eventually after a lot fiddling the DPM was laid with plenty of overhang.

Tomorrow I will lay the mesh on top of 50mm bricked so that the mesh is buried 100mm down from the top of the slab.

I will also make the shuttering that will determine the depth (150mm) of the slab.

The Building Control Surveyor is booked for a lunch time visit and we have provisionally booked the ready mix concrete lorry for Friday morning (no I am not going to mix this myself!).


The mesh has now been laid back onto the DPM using 50mm high blocks.

Wednesday, 25th April: Now comes the time to build the shuttering that will contain the slab when poured.

These are screwed to edge of the wall with the top 150mm above the foundation wall.

This will act as a guide when we are levelling the top surface of the slab - I'll add a baton to the house wall to match up.

It's been a bit of a rush but this is the completed shuttering and the Building Control surveyor is due any moment - fingers crossed!

Building Control visit Stage 4 - Oversite filling / mesh: Well, he's been. Everything is generally OK except for:

  1. The bits of slab I used to stand the mesh on are too large - they should be a quarter of the size I've used so I guess I need to get the bolster chisel out.

  2. I should have laid the mesh the other way round with the heavier cross bars going from the house wall to the long side of the extension. He will call me this afternoon after he has done a calculation - my proposal was to add additional steel rods going across - also I have a large square of mesh left over to throw into the pot.

  3. One of the slots is not quite deep enough as the mesh touches the bottom - some chiselling to do I guess.

Here is point #1 corrected.
The Building Control Surveyor rang back to say that he would be happy if I used the other piece of steel mesh as well - as long it was keying into the wall.

So this is what I have done.

Point #2 corrected.

He said he would pop round tomorrow just to check so it still looks like I am on for a Friday morning.
I did a bit more chipping out of the slots - Point #3 corrected.

This shows the outside top level of the slab clearly.
I've nailed some wooden battons on the wall to use as a guide when levelling the poured concrete tomorrow.
Building Control visit Stage 4a - Oversite filling / mesh: The Building Control Surveyor came around at 11:30 and OKed the work. So now it's on to pouring!

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