Crawfordsburn Diary Entry No.11 - The Waiting Game

We spoke too soon when we boasted about everything running on time! This week marked the start of the waiting game ... SIPFIT our timber frame manufacturer is running slightly behind schedule so were anxiously awaiting the arrival of the SIP Panels which should be any day now, fingers crossed. 

SIP Panels fabrication drawing

The drawing above was provided by SIPFIT which shows the manufacturing details and the panel layouts. We will discuss our choice of materials and the construction method in more detail when SIPFIT begin on site, which will hopefully be soon.

In other exciting news, this week we have had another client who has decided to proceed with their passive house. It's brilliant to see more people interested in this standard and indeed at the prospect of reducing their heating bills by up to 70%.

This has made us in the office re-evaluate, go back to the start and re-discover the basics of passive house design. As we have now successfully designed a passive house, we now know what to expect when it comes to design principles and we have identified the important factors of Passivhaus construction.

In case you aren’t already familiar with the five key elements of Passivhaus design, here they are ....

Insulation

Super insulation is obviously fundamental to Passivhaus construction. The passive house will have 225mm SIP panel walls and roof, and 200mm of high-performing Springvale Platinum Floorshield insulation in the floor. The junctions of these elements are of particular importance to prevent any heat loss.

Thermal bridging

We have covered this in previous blogs, but minimising thermal bridging is obviously crucial. In relation to the floor and foundations, there is inevitably going to be a thermal bridge from inside the building into the ground. We have tried to eliminate this by taking the 60mm block insulation in the walls down to meet the Floorshield rigid insulation, minimising the break in the insulation.

Airtightness

Airtightness is crucial for achieving low-energy performance. Considering the floor and foundations, a critical area for airtightness is the junction between the concrete slab and the walls, differential movement can occur here causing ineffective airtightness. The timber framing system facilitates successful airtightness as it can be lined with vapour barriers and airtightness tapes etc.

MVHR

The ventilation system, with heat recovery, is an integral component of the dwelling, essential for achieving the Passivhaus certification performance levels.  The MVHR system will quietly and efficiently provide the home with warmth when required, and fresh, filtered air all year round, improving the indoor air quality and reducing dust and allergen levels.

High quality glazing with south facing windows were possible

Passive use of solar energy is a significant factor in Passivhaus design and may reduce heating load substantially. It is desirable to have larger windows on south elevations and smaller windows on northern sides. This is ideal in the case of our site as the views offered from the south side are the most attractive.