Air Test Day

Monday was an important day with the first air test on the shell of the house. The previous few days had been spent making sure all the joints inside and out were suitably taped
Inside Window
Outside Window
So on Monday, a blower was installed where the front door will go. The idea being that the blower blows air from inside to outside and this sucks the air from outside to inside if there are any gaps.Blower DoorAnd how do you tell if there are any gaps? Answer – by using incense sticks. We smelled very fragrant afterwards.IncenseThere are some more photos on George’s twitter feed at

The results: 0.2 ach (air changes per hour) which every-one was very happy with. Apparently the Passivhaus standard requires less than 0.6, but our house will require less than 0.3 because of the number of windows. And that was including the cat flap.

And finally, Henry and Dan decided to play a joke on Mike by telling him that there was a big leak in the most awkward section of the ceiling where the pod meets the house.Air_Test_Leek

MVHR Installation

The Mechanical Ventilation and Heat Recovery unit is a vital part of a passivhaus. With an airtight house you need a way for fresh air to get in, whilst at the same time not loosing the heat in the house. Ours is a Paul Novus 300 which sits in the coat cupboard by the front door. MVHR pipeworkWarm moist air will be extracted from the bathroom, shower room and the kitchen. This enters the unit via one of the silver pipes, warms up the incoming air and the goes to the outside world via one of the black pipes. Meanwhile fresh air is brought in through the other black pipe and after being warmed goes out through the other silver pipe around the house.

So there is a lot of ducting as each room has either an extraction or supply vent.
MVHR DuctingUpstairs the ducts come up through the airing cupboard and then into the two bedrooms. If you look closely to the left of the window where there is an upright post you can see the extraction vent for the bathroom. Looks rather like a periscope at the presentMVHR Upstairs

Insulating with Warmcel

This week has seen the rest of the house covered in the green OSB boards, whilst the Warmcel team started blowing the Warmcel into the gap between the inside and outside boards. The photo shows the hose through which the Warmcel is blown. The brown circles show where application still has to occur and the pale blue squares are the airtightness tapes put over the plugs which are inserted after filling.Warmcel FillingA lot as already gone in, but as you can see from the mountain of Warmcel bales there is still a lot more to go.Warmcel Mountain
It has not been all insulation this week as the stud walls have gone up marking the two upstairs bedrooms. Our first chance to get a feel for what a room will feel like.Bedroom Stud Walls
And finally, on Friday the Colwall Orchard Group came back and planted another dozen plum and apple trees.

Green – but not as in eco

Whereas the outside of the house has gone blue, the inside is going a fetching green colour. The ceilings and walls are being covered in SmartPly VarPairTight: an OSB board which comes with an airtight layer already attached. SmartPly Ceiling The blue tape seals the cracks between the boards to make it completely airtight.SmartPlyOnce everything has been boarded the Warmcell people can start filling the gaps between the Ibeam joists with insulation.

Black and Blue – Weathertight

Since the last post, we have become weathertight with the last set of windows now up. The black of the title refers to the Resitrix rubber roofing which now covers both roofs.Resitrix RoofResitrix Main Roof
And the blue refers to the Siga Majvest blue rain and wind proof membrane that has been used to wrap the house up like a birthday present. This photo is of the North side where the front door is. Since the photo was taken small windows have been cut in the fabric, but quite a different look from the brown sheathing boards.Blue Walls

Weather-tight – almost

Last week saw the rest of the roof joists added along with a rainproof blue membrane. Nearly all the upstairs windows also went in. So now we are pretty much weather-tight with the exception of the tall two-storey window and the front door and window. Here is a picture of the main roof.Roof membrane
Now we can really begin to get an idea of the views from the windows – this is looking out of the landing window across the roof of Mike’s study.Landing View

Battening down the hatches

Saturday brought 24 hours of continuous rain, which meant that the ground which had been drying out is back to being a quagmire again. On Friday the ground floor of the house had been swept dry, but by Sunday there were again puddles up to an inch deep across the whole area as the continuous rain had seeped through the temporary plastic sheeting and the joins in the floor sheets above.

And then on Monday storm Imogen arrived. Not so much rain this time, but sudden very strong gusts of wind. I visited the site, to find the scaffolders had returned and were tightening up all their joints. The plastic membrane around the pod was also being battened down to stop it flapping in the gusts. It was rather alarming to stand upstairs looking through the landing window at the swaying silver birch a few yards away. However house and trees are still standing and the main roof is now nearly water tight so we are ready for the next storm.

First Floor Walls

This week the first floor upright I-beams were completed and the walls were clad with the fibre board, so you really begin to get a feel for the shape of the building. First Floor Walls
Then came another layer of I-beams, but this time they range in height to give a sloping roof ( from East to West ). The first roof joists have also been hung, which start to give us a feel for the height of the sloping ceiling in the upstairs rooms.Roof Rafters

Onwards and Upwards

Visually the house seemed to move very quickly this week, though it does look like it has been covered in cardboard. First the downstairs windows were added, with a few hiccups as explained in the previous post. Then Steico tongue and grooved woodfibre insulating boards were added. Ground Floor Walls
And then on Friday afternoon they started on the first floor I-beams and amazingly two-thirds of them were up in one afternoon
First Floor Beams

Oh dear – windows

We thought we were doing so well with the windows – they arrived in time for the build and they seem to be the correct number and size, but in true “Grand Designs” fashion we have encountered a little problem. All bar two of the opening windows and the patio door have their hinges on the wrong side.
As far as I can work out, it is a bit like the Mars Orbiter which missed Mars because one team worked in pound-seconds(Lb/s) and the other team worked in newton-seconds. This is what a window looks like at the plan stage – it is viewed from the outside and the point of the dotted V shows where the hinge is. Window PlanUnfortunately the window manufacturer does it different. The windows are viewed from the inside and the V point is where the handle is. Some-where along the supply line the drawings were incorrectly converted, though not consistently as not all the windows are wrong.

Fortunately we can work round it – two opening windows are fortunately the same size and can be switched. Other ones it did not really matter which way they opened. The biggest change has been to the patio door where the drawings shown the door on the left (as viewed from the inside). And as you can see from the photo it is now on the right.
Patio DoorWe had a session making sure it would not impact on where furniture could be put and on the whole it seems it might be the better place for it any-way.