Pitched Roofs
Issues to Consider Issues to Consider
Design Considerations
Full Fill Between & Under Rafter Insulation
Partial Fill Between & Under Rafter Insulation
Between & Over Rafter Insulation
Over Rafter Insulation
Partial Fill Between & Under Rafter Insulation
Breathable Membrane - Horizontal Installation on Continuous Substrate
Breathable Membrane - Vertical Installation on Discontinuos Substrate
  Nilvent Membrane - Vertical Installation on a Discontinuous Substrate

INTRODUCTION
Typical discontinuous substrates would be partial fill insulation between rafters. In roofs with a discontinuous substrate and a horizontally installed breathable membrane (see figure 3), it is not at all practical to seal the laps between the runs of Kingspan nilvent® and the roof should be considered as being unsealed. It would be preferable for Kingspan nilvent® to be installed taught it is not at all practical to seal the laps between the run of Kingspan nilvent® and the roof should be considered as being unsealed. Kingspan nilvent® can be installed taught in vertical runs from eaves to eaves, in one length, under counter–battens. If used in this way there will be no laps along the length of a run and laps between runs can be formed over a rafter where the counter–battens can secure and make an airtight joint. This method of installation can be less practical than the more traditional horizontal application, but it will yield a more energy efficient roof.

Figure 1
Vertical Installation on a Discontinuous Substrate
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PRODUCT DATA
Product Data
FIXING DETAILS
  • For ease of installation, thread a wood or metal bar through the core of the roll and set it on bearers on the scaffold platform.


  • Fit an eaves strip of UV–resistant material to overhang the eaves/fascia by 50–60 mm.


  • Lap the Kingspan nilvent® logo–up over the eaves strip (if required) with the bottom edge of the Kingspan nilvent® in line with the top of the fascia.


  • Kingspan nilvent® should be laid taught.


  • Each run of Kingspan nilvent® should be installed in a single piece from eaves to eaves.


  • Temporarily tack in place with staples or clout nails and cut to length with a sharp blade.


  • Move sideways and repeat the process.


  • The second run of Kingspan nilvent® should lap over the first by 100 mm with the joint positioned as to coincide with a rafter position.


  • The printed tramlines on the top surface of Kingspan nilvent® indicate 150 mm.


  • Laps should be sealed by counter battens fixed at 300 mm.


  • Continue installation across the roof in the same manner, then install slate/tile battens over the whole area installed.

Figure 2 (Ridge Detail)

  
Ridge Detail
Figure 3 (Alternative – Horizontal Installation)
Horizontal Installation
NB For horizontal installation on a discontinuous substrate install the Kingspan nilvent® so that a valley is created between the rafters for rainwater drainage making sure that the horizontal overlap is 150 mm except for pitches of between 12.5 and 14.5 degrees where 225 mm is required.