The Ampack Market leading 10 year warranty covers the cost of removal of all affected material, as well as the replacement of all damaged materials.

10 reasons for an airtight House

1. In the case of new buildings a permanent, airtight layer is now essentially a requirement.
2. New building regulations ensure that the assigned certifier must have correct detailing to avoid future construction damage
3. No draughts
4. Lower heating costs
5. No condensation in the construction
6. No mould formation
7. No damage to the building
8. Clear improvement in the quality of air in the rooms
9. Clear improvement in sound insulation
10. Ventilation systems work highly efficiently

These days, homeowners and clients expect more in terms of quality in their  homes. In particular, they pay special attention to their climate: It has to be comfortable, It should not damp or too dry and the energy costs must be kept within reason. In other words: Everything should be right, with no ifs or buts. Which is one more reason why the construction of new buildings should always be airtight.

Build well, build airtight

Heat loss due to a lack of airtightness is extremely expensive and can potentially cause great damage. The installation of a high quality airtight layer protects both your wallet and the value of the building. The amortisation of the investment over many years is clearly more relevant here than the short-term cost considerations.

Even the smallest joints and tears in the building shell can cause disastrous amounts of damage to a house and result in clearly escalating energy costs.

Construction Damage

Thermography: Blue = heat loss
resulting from ventilation = increase
in energy consumption and structural
damage.

Mould formation within a multi-layer
structural component.

Partel are the exclusive Irish and UK agent for the Ampack range of airtightness, wind-tightness, and building protection products. Ampack was founded in 1946 and is one of Europes most established specialist membrane and tape manufacturers.

“Our Ampack products offer a complete building protection system, from radon membranes to airtight membranes, tapes, adhesives, and wind-tight membranes, and Ampack’s unique 10 year guarantee ensures customers confidence in our range” .

Achieving airtightness for the new building regulations. 

At Partel we have worked on a standardisation of robust airtight details designed to ensure the following: -

1. Compliance with building regulations
2. Quality detailing to achieve excellent blower door results

Our details when applied correctly will always exceed the current building regulations and achieve lower than 0.6 air changes – the passive house standard

All of construction drawings are  available for free download at the links below

• Ampack Masonry construction details
• Ampack Timber frame construction details
• Tender Text External Systems
• Tender Text External Systems

Auto cad drawings available on request – contact us here 

Often referred to as airtight membranes know but should be classified as -

1. Vapour Checks
2. Vapour Barriers

Before we discuss the differences in 1 & 2 we need to discuss Vapour resistance, SD values and μ values.

Vapour resistance

The vapour resistance of a material is a measure of the material’s reluctance to let water vapour pass through. The μ (“mu-value”) of a material is also known as its “water vapour resistance factor”. It is a measure of the material’s relative reluctance to let water vapour pass through, and is measured in comparison to the properties of air. The μ value is a property of the bulk material and needs to be multiplied by the material’s thickness when used in a particular construction. Because the μ value is a relative quantity, it is just expressed as a number (it has no units)

Equivalent air layer thickness (sd value)

You might see the reluctance of a material to let water vapour pass through expressed as an “equivalent air layer thickness”, which is usually represented as sd. As its name suggests, the equivalent air layer thickness is measured in metres. Like vapour resistance, it can only be quoted for a particular thickness of material. The higher the SD Value the more resistant to vapour transmittance.

To convert an equivalent air layer thickness to a µ-value -sd is the symbol for equivalent air layer thickness

Divide by thickness in metres

Example: For a material with : sd = 2,000m and thickness = 100 mm, we have µ-value =2000 m / 0.1 m = 20000

3 Rules for the correct Installation of Vapour Barriers and Vapour Checks

1. Working ventilation or vapour permeable layer. low SD value. DB90, DB2, Sisalex 500

2. No Ventilation between insulation and vapour retardant outer skin.  Vapour barrier  with high SD value Sisalex 514 >1800

3. Locations with constant relative humidity such as swimming pools. Vapour barrier high SD value  Sisalex 514 >1800

Incorrect installation will lead to construction damage!

The images below show roofs where a Vapour check should of been installed.

Incorrect installation or lack of appropriate membranes can cause issues with insulation functioning as specified leading to lower U Values, dampness, and structural damage

What is WUFI
WUFI – Oak Ridge National Laboratory (ORNL)/Fraunhofer Institute for Building Physics (IBP) is a menu-driven PC program which allows realistic calculation of the transient coupled one-dimensional heat and moisture transport in multi-layer building components exposed to natural weather. WUFI-ORNL/IBP is based on the newest findings regarding vapour diffusion and liquid transport in building materials. The underlying model has been validated for over 20 years.

Hygrothermics
Besides the thermal properties of a building component and their impact on heating losses, its hygric behavior has to be considered, too. Permanently increased moisture content in the component may result in moisture damages. Elevated surface moisture levels in living rooms can lead to hygienic problems and health risks due to mould growth.
In addition, thermal and hygric behavior of a building component are closely interrelated as well as an increased moisture content favors heat losses. The thermal situation affects moisture transport. Therefore, both have to be investigated together in their mutual interdependence; the research field of hygrothermics is dealing with these problems.
Out of Date: Dew-Point (Glaser)
The Dew-Point method as detailed in American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) handbook has been a common method to assess the moisture balance of a building component by considering vapour diffusion transport in its interior. However, this method does not allow for the capillary moisture transport in the component, nor for its sorption capacity, both of which reduce the risk of damage in case of condensation. Furthermore, since the method only considers steady-state transport under heavily simplified boundary conditions, it cannot reproduce individual short-term events or allow for rain and solar radiation. It is meant to provide a general assessment of the hygrothermal suitability of a component, not to produce a simulation of realistic heat and moisture conditions in a component exposed to the weather prevailing at its individual location.
Up to Date: WUFI-ORNL/IBP
The menu-driven PC program WUFI-ORNL/IBP developed by the Holzkirchen branch of the Fraunhofer IBP and ORNL validates using data derived from outdoor and laboratory tests, allows realistic calculation of the transient hygrothermal behaviour of multi-layer building components exposed to natural climate conditions.

To meet new U -Values for building regulations, achieve passive levels of airtightness and to minimise thermal bridging should we abandon the cavity wall in favour of timber frame or externally insulated masonry?

There are issues to overcome but what does cavity wall still offer that External Wall Insulation or Timber frame construction does not ?

• Familiarity to Architects, Engineers, Builders, tradesmen and home-owners
• Cost
• Skills
• Knowledge
• Lack of certification for newer products

What are the issues?

• Thermal bridging at Ground, floor, roof, windows and doors.
• Suitability for achieving airtightness
• Breathability
• Speed of construction

We believe that the downturn in economy has negated the issue of speed somewhat and the cost competitive nature of the industry has inspired architects and builders into finding new ways of overcoming the issues with cavity wall construction.

We recently worked with Greentec Eco homes on a passive cavity wall construction project that used quinn lite blocks to minimise thermal bridging at foundation level,  teplo ties as part of a 250mm pumped cavity wall, Ampack Airtight tapes and Membranes  to achieve a passive level air change rate of 0.37 ac/h, and innovative treble wallplate detail free from thermal bridging.

Manufacturers appear to believe the cavity wall is here to stay with Ampack  now producing 4 new airtight window tapes for Ireland and cavity walls – they can be seen here (Ampack Window installation tapes). Aeroboard producing supergrund foundations suitable for masonry, Xtratherm developing and producing Thin-R plus full fill cavity insulation, and teplo ties facilitating full fill cavity insulation up to 300mm.

A paper by Joseph Little of Joseph Little Architects studies the issues in greater detail  and while last updated in 2006 is still worth reading Partial Fill Cavity Walls: Have We Reached the Limits of the Technology? This paper while identifyng the positives and negatives also serves to highlight the changes and solutions that have been developed since 2006.

While timber frame and externally insulated masonry may offer  advantages in terms of speed, suitability for airtightness, and thermal bridging it is clear that the modified cavity wall has a future as it can compete on price, and has greater flexibility for finishes and cladding and is engrained in construction in Ireland and the UK.

Water comes from the outside? Well, yes …. but more moisture might be permeating the construction from inside the building shell than from the weather.
When vapour checks and airtight layers are used in accordance with
the standards, they provide the following benefits:

• Energy losses are reduced
• Condensation is avoided in the structure
• The formation of mould and structural damage is avoided
• Pollutants are avoided in the air within the rooms
• The noise-reduction mass in structural components is guaranteed
• The insulating effect of structural components is guaranteed
• The ability of ventilation systems to work properly is guaranteed

Therefore, it very quickly be comes clear that an incomplete or badly-fitted airtight layer bears a huge risk of damage and danger. We new have the correct membranes available to ensure the above problems do not occur. For more please see www.theinsulationstore.ie

Thermography: Blue = heat loss
resulting from ventilation = increase
in energy consumption and structural
damage.

Mould formation within a multi-layer
structural component.