The 2 Story Rear Extension

The time has finally come to stop procrastinating with the little jobs and get on with building myself a new bedroom

This Project is Still Ongoing (and will be for some time!)

I’ve spent a lot of time planning and designing this extension, researching everything from cranked vents to ridge boards.

What Do I Need to do?

A fair bit!

The DIY tasks ahead of me are huge but I’ve designed everything so that nothing is beyond my means and if I do come across something I’m not sure about, I’ll just wing it. Rather than list all the individual DIY tasks, which will be a bit boring, here’s a run down on the extension, let’s start with some layouts that I used for planning:

rear elevation in simple black and white for planning purposes. showing windows and doors and balcony
The Rear Elevation looks at the extension face on, as it projects out from my existing house. You can see the balcony with two side walls

plan view on ground floor of extension showing large combined kitchen and diner
The ground floor layout is pretty simple – a combined kitchen diner with a very wide sliding door leading out onto some decking

plan view on first floor of the extension showing main bedroom with en suite and walk-in wardrobe
The first floor is a large bedroom (the bed is a super king, so makes the room look small) with a generous sized en suite and a walk in wardrobe (10% mine, 90% for the missus)


Just for a bit of fun, I have a go at estimating the cost & time

Well this is tricky. A total stab in the dark here and I reckon I could build the lot for £35,000.

On the timings, another total stab in the dark and let’s go for 14 months, by mid Summer 2020.

Daily log

A brief log of my battles with the tasks! with a few pictures chucked in…

January/ February 2017 (before this website)

The first thing to do with any new project is to get surveying, and for a 2 story rear extension, this is quite a bit of measuring!

Once measured up , I drew my existing plans and elevations:

line drawing showing the existing rear elevation of sams house, as if looking from the rear garden. four windows, some downpipes, the roof and chimney
Rear Elevation of the back of my house, as it was before any work started. It’s necessary to include drawings of the existing house as part of the planning application
plan view on the existing ground floor layout, showing kitchen, lounge, porch, garage, dining room and downstairs loo
Complete ground floor plan extending to the adopted road at the front of my house and half way up my rear garden. I was including a shed as part of my planning application and this was located right at the front. Normally, going that far in front isn’t necessary for a rear extension
plans showing the first floor layout as if looking down, like a map. also a plan on the roof. the first floor layout shows the existing bedrooms and bathroom
Existing first floor layout and combined roof plan

The survey drawings are pretty simple. It took me 2 months to survey the house and draw it all up, that was in my spare time.

March/April 2017

It took me a further two months to draw up the set of plans for the planning submission. This took quite a bit of thought as we new we wanted a balcony but realised that would be tricky to get through planning. Mainly due to the invasion on our neighbours privacy.

rear elevation on the proposed extension. labelled up with white render walls, grey windows. There is a large 3 bay sliding door and window on the ground floor and a smaller sliding door and window on the 1st floor
ground floor layout showing the new extension. The extension on the ground floor is one large combined kitchen/diner
You can see I also included the proposed new front porch as part of the same application
1st floor plan on the proposed extension for planning. showing a new master bedroom, en suite and walk in wardrobe. The roof of the garage is new as well and the porch roof is shown out the front
The roof of the new porch is shown here as well as the new pitched garage roof (currently flat roof, yuck!). In the new extension, we have a master bedroom, large en suite and walk in wardrobe
plan on the new roof of the extension and how it interacts with the existing roof

Once all the plans, existing and proposed, were made, I filled out the form and popped it all in the post to the council and commenced biting my nails! Was a nervous time as we’d bought the house with the sole intention of having a new master bedroom, en suite and especially a balcony!

November 2018-January 2019

So a bit of a gap there! I got the planning approved after a few compromises (many thanks to my neighbours!!!!) and over Christmas 2018 I got on with the detailed design. I’d already shipped the approved planning drawings to an Engineer for some structural input, and he’d come back with the structural items to include in the build. These were things like beam and columns specifications, some details, foundation design and lots of other specs for me to adhere to.

The new drawing included loads of close up details and sections, so I knew exactly what I was going to build and how to build it.

detailed architectural drawings for sams 2 story rear extension are laid out on the floor showing sections, details, plans and elevations

Week beginning 11th February 2019

Finally starting on the extension this week and I realised I have to remove about 50 cubic metres of soil by hand, into skips! This lot weighs approximately 60 tonnes! That’s about 8 large skips. Still, I’m doing the London marathon in April 2019 and this is just really good training.

a skip lowering 2 skips onto sams driveway ready for the excavations for foundations
I had two skips delivered at the same time because I knew I could fill them up quicker than they could take them away.
view from 1st floor looking down onto the digger, with sam on it digging the foundations and stripping the site
End of day 3 – At this point the mechanical wheelbarrow had broken down for the 2nd time that day, so it was back to the manual barrow!
at night with some lights lighting up the excavation, sam is spray painting the ground to set out the extension foundations

And once it had got too late to dig, I did some setting out

26th February 2019

Today was the day for pouring the foundations, but first the excavations had to be inspected by the local building inspector. After a 2 minute “inspection”, and a comment questioning the depth of the foundations (the one’s next to the 10m high tree), I was pleased to hear all was well, and I could proceed with the concrete pour.

I calculated I’d need around 18 cubic metres of the stuff, that’s about 43 tonnes. I had the help of two others, so we started off the day by placing planks over the trenches in readiness for the barrowing.

top down picture showing excavated foundations ready for concrete pouring. Planks have been laid over the trenches to allow wheelbarrow access with the concrete. claymaster heave protection has been fixed to the sides of some trenches.

I also had to secure the Claymaster heave protection foam sheets to the sides of some trenches (they’re the white sheets in the picture above). For some reason, I opted for us three to barrow the concrete from the front. To this day, I don’t know why I didn’t just get a pump, it would’ve been so much easier! Needless to say, it was hard work, so I stopped at 12 cubic metres (two mixer lorry’s), leaving the top of the concrete lower than planned. At the time, I figured I’d just use more blocks to build the walls up from the lower foundations, not realising that it wasn’t quite this simple, as I’ll explain later.

top down view on foundations having just been poured with concrete

2nd March 2019

Now it was time to start putting the blocks in place. Before this, I had to set-out the outline of the building and its corners, so I knew where to lay the first blocks.

sam is stood on the foundation whilst pulling the string line tight. Caitlin is watching
Setting out using a stringline to make sure the extension lines in with the existing house

Once I’d set everything out, I began laying the blocks. By the end of that day I’d got a few in, then it started to rain!

And it rained, and rained, for months. The trenches became submersed in water and the only way to remove it was to pump it out.

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