Steady does it ! : Airtightnes, floor build, rainwater reuse

The job is progressing well, tying up lots of loose ends ; the airtightness test is now scheduled which will be a moment of truth for us all. If you're not familiar the Passivhaus requirement is for 0.6 airchanges per hour when the house is pressurised to 50Pascals ( equivalent of a storm force 5 I believe). This is about 10 times the airtightness required by building regulations( which are signed off/ detailed on paper by an architect/engineer rather than field tested).

Inside we're been moving stud work to get the doors correctly positioned and the floor is now being built up with 400mm of polystyrene. When you actually see this much insulation under the floor it is quite a shock. The large rainwater tank is due tomorrow to go under the garage. Also the sections of flat roof have now been completed ( in a light grey colour) & we'll test these with a hose now shortly.

So far the self build option is going well, particularly as I did a lot of research on the field of Passivhaus before we even started & gained the PHI qualification earlier this year. The challenge with self build is that if something doesn't work, then it falls back to you, & your wallet, to rectify - rather than having a contractor who takes the hit / risk & of course charges a risk premium for that. This is particularly important for something like a certified Passivhaus which has to meet very specific performance criteria or else it fails. The old addage is that the person who has most control over the process is the person best placed to take the risk. In a PH self build this means if that you dont fully understand the required outcomes & how to get there then  this route is likely not for you. For a regular self build though - without the strict performance criteria - then this simply doesn't hold though & its is a lot less daunting. Towards the end of the job I'll do a better job of the pros & cons / ups & downs  of the route we chose.

The transition from the structural elements onto services & finishes

Well, been a interesting 2 weeks since the last post. Still in the transition phase between wrapping up the structural work and starting on the internals.  Its an interest point in any project where the main decisions have been make, the money allocated or spent - well, now is time to execute, make sure that its done properly and no shortcuts taken. Its a tough market on construction companies and people will bid tightly for work, often too tightly. However tempting, make sure that whatever you agree and has been hammered out over discussions, that its noted down, best signed by both parties...even better an diary is a great idea. Just recently I've started to note down peoples commitments / observations on a phone App under the trades - this has been a real asset for logging issues and is very handy on the phone.

On the outside the Parex Lanko monocouche basecoat render will be applied next week. The various flat roofs cannot the full completed until the render is applied. The foundations for the garage were started this week and we're going to put the concrete rainwater harvesting tank under the garage. This system will  have UVs and filter treatement and will be used for all domestic hot water....showers in rainwater!

On the inside and ducts are being run, with attention to be paid to any pentetrations through the foundation blockwork. Some of the services runs have been a bit of a challenge, the fact we went with vaulted ceilings and for a warm roof construction ( ie insulation is on the slope rather than tradition Irish approach of insulation on the ceiling with a ventilated attic space) has made routing a lot simpler. This warm roof construction is still rather new in many countries and the detailing of it properly to eliminate cold briding must be worked out in advances & well implemented in site.

On a lighter note, the daffodils are in full flower and we planted another 20 silver birch and beech during the week. This has really started the process of turn it from a construction site to a house and garden.