HPH221 : The build schedule for my cavity wall Passivhaus home – with Ben Adam-Smith
As Ben Adam-Smith's build enters the final few weeks he reviews his project's schedule and sequencing. Although a lot of the detail pertains to building a masonry wall Passivhaus, it still serves as an example of the stages any house build might go through.
And just a quick note before we start. This podcast has been put together reflecting on the photo vault that I have amassed during this project. That means I'm going to be using simple language and it's entirely possible I'll be missing big pieces of the jigsaw!
For an overview of the technical design of this project, check out our interview with Dan Higginbotham from Parsons + Whittley.
Month 0 (December)
As we started mid December 2017 this was about two weeks of work so I'm calling this ‘Month 0'.
Our main contractor Mars Builders set up the site first.
Tasks included erecting the heras fencing to make the site secure, creating a designated parking area, preparing the shipping containers for storage, opening up a site office and hiring a portaloo.
Once this was achieved the site was marked out and they started excavating.
Foundations, services and superstructure
Month 1 (January)
Quite a lot happened this month.
The shuttering for our strip foundations was put in and then the concrete was poured.
Once levelled, dwarf walls were constructed and the service pipes were put in.
A beam and block floor went down next . . . followed by some insulation, a damp-proof membrane and the plinth.
By the end of the month the blockwork superstructure was well underway. The first lift (up to the first floor) was almost complete.
Joisting, boarding and second lift
Month 2 (February)
Lintels were added to all ground floor windows.
As our open plan kitchen, dining room and living room is big we needed one section of steel. That went in this month.
The first airtightness membranes went in around the posi-joists.
Once all the posi joists were in, the first floor was boarded and the second lift blockwork began.
Finally for this month the trusses were erected.
Roofing, airtightness membranes and stud walls
Month 3 (March)
This month we moved a step closer to being watertight. It started with getting the roof felted, battened and tiled.
Then cavity closers were added around all window and door openings. Installation would probably have followed but there was a slight delay while we discussed with our engineers the final details of supporting the heavy triple-glazed units.
Upstairs the ceiling was boarded and then an airtightness membrane was added. The catslide roof (which we required in order to gain planning permission) was insulated.
Although masonry construction throughout downstairs, the partitions upstairs are stud walls. These flew up this month along with a false ceiling where our MVHR ductwork would be hidden.
Window, airtightness detailing and first fix
Month 4 (April)
This month the windows were installed and all the associated airtightness taping was carried out.
First fix electrics (cabling) and plumbing (pipework) also kicked off.
Downstairs an airtightness membrane (it looked very like a bin liner!) was added and the floor was insulated.
It was at this point that we had the preliminary airtightness test. This shows that you're in the right ball park because not all the airtightness layers were in place (the doors were yet to be installed and the walls were not plastered).
Then the floor was screeded downstairs.
Upstairs sound insulation was added to the stud walls and then they were plasterboarded.
Doors, rendering and plastering
Month 5 (May)
With the installation of the doors, this month the building became watertight.
The scaffolding was reduced so that the exterior could be rendered.
Inside, the MVHR ducting downstairs was also completed so that the ceiling could be closed up.
Now the plastering could begin internally.
Other jobs included putting up the weather board on the garage, initial landscaping in front of the house (including a hole for the soakaway) and digging a service trench out to the main road.
Inside the stairs went in and in the attic space the thick blanket of insulation was laid.
Decorating, services connected and tiling
Month 6 (June)
Rendering and plastering could be ticked off this month, and the scaffolding finally came down!
The decorating also began, including things like our feature walls.
In the bathrooms the first fix plumbing was completed, allowing the bathrooms to be tiled.
The second fix electrics (adding plug sockets and light switches) also got underway upstairs.
Outside, the porch was constructed. And we were connected to mains sewerage, gas and electricity this month.
Second fix, flooring and kitchen
Month 7 (July)
Our project has a fair bit of bespoke carpentry and this month it was made on site.
Second fix plumbing began (installing basins, loos, showers, etc.) and second fix electrics moved downstairs.
Once the floor was laid, the kitchen and utility room base units were installed.
Outside, a pathway was excavated around the house and the sleeper retaining walls went in.
M&E, snagging and landscaping
Month 8 & 9 (August and September)
First I must point out that this is where we are in real time! *I will update this section once the work has been carried out.*
Anyway, I can give you a sense of the jobs that are still on the to-do list.
Inside the house the kitchen worktops need to go in and the last of the plumbing and electrics needs to be finished off.
There are little decoration jobs around the house (such as wallpaper in one room, brick slips in snug, etc.).
Finally the radiators, boiler and MVHR need to be installed and commissioned.
No doubt there'll be all manner of snagging too!
Outside the balcony needs to be constructed and the garage floor needs to be laid.
Is there anything else? Oh yes, the site fencing needs to go up, the garden needs to be seeded and the driveway needs to be laid.
As mentioned earlier this list has been in no way comprehensive but it should give a sense of how the work has been carried out.