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.

18 March 2011

Bit of a transition happening on site as the timber frame work closes out & Baker & Co are working on the aitrightness. Any of the perforations of the  air tightness layer & insulation need to be planned at this stage and then properly sealed / dealt with.  We're probably about 3 weeks away from out preliminary  air tightness test. The scope of the services has been agreed and equipment choosen - I'm not going to jinx myself by naming brands until I've seen them perform!

As regards site works, have returned all the information needed by the utility companies so that process is slow but at least its stated.

Here in Ireland its coming to the end of bare root planting season. You might ask why in this blog thats anyway important. Well , the main reason is that a tree like silver birch is a fantastic source ( technically & cost wise) of solar shading to limit building over heating : no leaves in winter & loads in summer. So we got some trees - about 3-4m high from Tully Nurseries in north Dublin ; Toby there was great in giving us direction on what to choose & general advice on planting.

Have included a few photos below of what the air tighted windows looks like on the inside with a 100mm service cavity looks like on the inside.

General Progress

The exterior render board has now been fixed to the building & the seams between the sheets rendered; this sits proud of the building bu about 50mm which will allow us to run any services e.g. lighting wiring, along the outside of the building concealed. The flat roofs are also going in , just need to make sure the drip for the cap is away from the render & the metal cills below. Inside the insulation ( the fibreglass batts)  on the exterior walls has been fully installed, the exterior walls are now being airtighted with OSB & Siga airtight tape. If you've not seen airtightness tape before this is an amazing product - super sticky & lasts for decades apparently

Also received my Passive House Institute Certification as a Passive House Consultant today following the exam in December - it was an excellent course covering the design principles and details  of such low energy house design

Suppliers We are using Part 1

Completing this house & getting it certified by the Passiv Haus Institute (PHI) has meant using suppliers who have both a good product, consistent attention details & can install it well it well on site. In order of installation:

Timber Frame
Great quality frame from this family run business; Mark Cooper is the contact
www.kilbroneyhomes.com/

Insulation & Airtightness - Baker Insulation 
A family run company with great attention to detail on site; Mark Baker is the main man 
www.bakerins.ie

Passive House Construction Update : Airtightness, External Render System, Insulation Installation : Progress Update 2 March

Pace on the build has really increased in the last week. The roof is now fully complete & they exterior board ( no block!) is going up on the outside. The board which sits proud of the building by approx 50mm to give a ventilated cavity round the structure will then receive a permanent monouche render.

Inside the insulation work, airtightness membrane sealing & putting up the OSB which will be the internal aritightness layer and provides racking strenght. The service cavity will be further inside the OSB them. The insulation being put in by Baker Insulation is a slab form of fibreglass which comes in blocks ( rather than rolls) & reduces the chance of sagging over time.  There is over 300mm in the external wall buildup and an additional 100mm to go into the internal service cavity - this should give a U value of around 0.1 W/m2K; We are targeting similar U values for the roof and the floor. We're using Siga products throughout on the airtightness due to their proven longevity. Kilbroney are even taping over the nail holes where they put up the sheets of the 18mm OSB sheets

Photo below of the vertical battens on the structure ready to receive the render board & further photo below of the first few sheets applied. The product is from REP and which it has no thermal properties, it should never need painting and is one of the few such products where no moss  / discolouration has been noted in Irish conditions.

Insulation for the floor slab is now on site & will be put in shortly. penetrations though the slab will be identified at the same time as the insulation is installed. All looks OK with the bathroom  / sanitaryware order from Reuter Badshop in Germany. Starting to do planting tommorow as we are running out of time for planting bare root stock. Daffodils are now up on site - photos to follow!

Update - Fri Feb 19

Its been a fairly busy 2 weeks. Physically the windtight wooden structure is up and most of the slates are on the roof. Windows have been installed  but the opes are not fully sealed.  There is a photo below of an installed window with the cill sitting proud of the panelvent / breather membrane. We're battening the outside of the building in preparation for the cementation board & internally, insulation ( from the inside) should using a dense rigid fibreglass start next week.

Bad news this week was the one of the nights, some uninvited guests to the site removed most of the lead valleys from the roof. Have obviously not been found.

Big decisions this week included

• Mechanical systems ( in particular the heating system and the extent of the rainwater recovery which due to water being free in Ireland at the moment, has an infinite ROI...go figure); quote & scope agreed
• Electrical : extent of cabling, type of data cable etc..awaiting quote
• Colour of the external render - its a permanent colour so need to get it right
• Bathrooms - ordered from Germany, ETA about 3 weeks, hope this decision does not prove 'interesting'
• Wood flooring - purchased
• Landscaping - awaiting final quotes for the supply of bare rooted trees will need to be put in the ground by the end of March to catch the growing season

Progress update 7 Feb

Lots happening at the moment. Up on site the windows arrived from Germany on a truck this morning ( see photo) & are currently being installed. As with all window suppliers there is an approximately 50% payment due on order placement  - which is a leap of faith, trust me. A further approx 50% is due on delivery & checking to site; an residual then is due on installation. These are industry standard terms so not much one can do about it. The windows are triple glazed alucad from Pazen & they are PHI ( Passiv Haus Institute) certified; the wood on the inside is a painted eucalyptus (sp?) and the outside a pearlised silver, which looks grey to me! Only issue with the aluminium colour finish is that any scratches during construction will be hard to remedy / hide. So far so good though.

As regard utilities, we road (approx 150m) with services and stormwater to installed. BG & ESB have been out and we've received quotes for their utility installations ( which they do themselves). The foul, water & stormwater we do ourselves but the council does inspect to make sure  its up to standard.

Slates will be going on the house roof now shortly - delays caused by recent very high wind - photo below shows the wind tightness layer, felting & battening complete.  Pretty soon we'll be working on the inside in particular the wall /roof  insulation , airtightness layer, slab insulations & screeds. There are a number of items that can have a lead time so we're looking at these now with an eye to placing orders soon. Will probably order the bathrooms / sanitaryware from Germany due to the massive cost differences - approx 30% - dont worry this isnt going to shrink the budget , just move us up the quality scale.

At the same time we're looking at site landscaping as you can plant bareroot plant between now and the end of March & still get a growing season in this year. The alternative is to get rootballed plant / trees - these work out about 3 times more expensive. 

Closing in the Passive House - Putting on the Roof

Kilbroney Timber Frame have made great progress in the last 2 weeks. The roof is now going on, we've decided to go for a warm roof, which is unlike most Irish roofs (where the insulation is on the flat of the room ceiling) in having the insulation on the slope at rafter level. In addition the build is being made windtight ( as evidenced by all the tape) using Siga products and the roof will have a sarking board ( 9mm panelvent, a vapour diffuse wood fibre sheet) to decrease wind infiltration into the structure. Warm roofs, wind tightness and sarking board are very common techniques in Europe and Scotland but are not common in Ireland yet - I strongly suspect they will as they dramatically improve building thermal performance quite cheaply.We have used Panelvent in preference to other products due to its wind resistance and ability to release any condensation that occur ( i.e. breathability) rather than trapping it like some products like OSB do. in addition the frame is covered in breather memebrane on the outside and is windtight using siga products.

Also we're looking at the plumbing, heating and bathrooms to finalise the requirementd and get equipment and sanitaryware ordered. The windows arrive in mid February at which stage the building will be weather tight & internal works will start at pace. We even started putting in some plants last week as this is prime planting season.

Also work will be starting on running services - gas, power, comms, foul, water, stormwater - over the next few weeks now that much of the heavy vehicle movement is over and hence damage to newly buried services will hopefully be limited. Will be interesting to see how busy the services providers are at the moment & how much they will try to charge!

Passive House Self Build : Snow & Progress

Weather in Ireland in December was obviously fairly poor , now just as we start the new year we are up at tool level with all the main structural walls up and the roof, including slates, due to go up over the next few weeks. We are very happy with the quality of the structure and with the attention to detail being paid to airtightness, this should result in a good airtightness result from the preliminary test in a few months. The initial documents are going to the Passive House Institute in Germany shortly which should help smooth the process.
The windows are now due to arrive in about 6 weeks ( mid Feb) so by the end of February we will have a well sealed building and the initial internal works ( insulation, airtightness, mechanical & electrical ) will start then. A few photos of the last few weeks attached.

As the detailing of how the build is to be completed has been agreed in advance there are less variables on site. However, the protection of the airtight layer, some of which is installed as the frame is being erected, is paramount.