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


Pouring the foundations

Friday, 13th April: Building Control visit Stage 2a - Foundation excavations: The Building Control Surveyor came around at around 12:30 and was satisfied with the trenches. I had a long chat with him about floor slabs and walls - more later.

Let's start concreting!

I started with the lower trench and built a bit of shuttering around the mains water pipe. This will be filled with pea shingle and covered with a concrete slab later.
I ordered 12 concrete bags - small ones so that can put the whole bag into a single mix of foundation concrete.

I decided to get the stones in small bags as I didn't know how many I would need - this was probably a mistake!
This is my trusty 25-year old Polish concrete mixer - still going well.

The foundation concrete mix I used was 1 part cement, 2 parts sand and 4 parts aggregate.

I found that one barrow load would cover an area of about 600mm by 600mm to a depth of 7" (how's that for working in two different standards!)

Phew, this is dirty and hard work!

Done finally - 6 mixer loads and two hours later.

You just see the three reinforcing steel bars that straddle the two level changes.

The higher level needs to overlap the lower one by about 300 to 400mm as shown in building regulations below.

Source: On-line Building Regulations (Planning Portal)

Saturday, 14th April: I got up early this morning - very hot again and perfect weather for laying foundations.

Went an got a load more bags of stones and some more bags of concrete.

Let the mixing begin!
I did the middle section first but as I had to dig down 800mm in the bottom trench it looks like I will have to add another step in the foundations.
The top section is now done.
In fact the whole trench is now completed with three steps and you can see the wooden shuttering used to form the steps.

I am going to place a couple of concrete slabs over the old drain so I built a step to the side of it to hold them.

All I need do now to finish the foundations is to add two buttresses so that the foundations at either end cover half of the existing house foundations. These will be about 500mm long.

To get to where I am I have used 15 mixer loads of concrete! Phew.

Removing the shuttering reveals the steps.
Sunday, 15th April: To finish the foundations I just needed two more loads of concrete to build a buttresses from the new foundation to half cover the existing house foundation.

This is the south end of the extension.
This is the north end of the extension.

I can now call out the building control survey to look at them - fingers crossed that they will be OKed!
The north buttress.
The south buttress.

I have to admit that they do look look like WWII German bunkers...
All ready for a Building Control inspection tomorrow.

It was near thing this week as there seems to have been a fire at a cement processing factory. Wickes and B&Q have been completely out of stock all week - I managed to get the last 12 bags from B&Q last Saturday!

Building Control visit Stage 3 - Foundation concrete laid: The Building Control surveyor came this morning and approved the foundations - hooray!

So now on to building the wall up to the bottom of the slab.

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