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


Possible sewer drainage issues

As mentioned earlier, the main issue that will determine the level of the floor inside of the extension is the current level of the main house sewer drainage pipe and the level of the inspection manhole (Drain #2 below). I want to remove the two steps up to the back door so that the level of the floor is as indicated.

This will cut a slice off the top of the inspection chamber. If the distance between the between the top of the drainage pipe as it enters drain #2 inspection chamber and the proposed floor level is too little the main drainage pipe might have to be lowered or the floor raised.

Showing the position of the drainage inspection chambers (accurate scale)

Showing the main drainage pipe looking underground (accurate scale)

Fortunately it looks like the distance from the floor level to the top of the drainage pipe is around 30 cms (12") so there is still plenty of height in the inspection chamber. Hopefully, the proposed level of the floor in relation to the drainage pipe is fine.

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