Barn conversion insulation: The perfect combination of old and new



Bringing a barn into the 21st Century

Converting an old barn into a liveable space brings a redundant building into the 21st century and can be a priceless addition of character to any home or commercial building. One of the key alterations you may be considering is the addition of thermal insulation to make the building comfortable and energy efficient, but since they are steeped in history, any work carried out should be sympathetic to its original state, retaining features such as stone walls and exposed rafters. When it comes to upgrading roof insulation, barn conversions are amongst the most challenging projects to take on due to their varying degrees of disrepair, their age and their location. Generally positioned in remote, rural settings, they are exposed to the elements, therefore require an added level of protection compared to modern builds. Adding the required level of insulation can be rather tricky given their unique character, with shallow, irregular rafters and solid walls not conducive to a fully efficient insulating system. Multifoil roof insulation helps to manage the common problems associated with difficult to insulate buildings and maximises the space available to make your internal living environment as comfortable as possible. Our multifoils do this by carefully managing heat transfer and mitigating condensation risk.  Keep reading to find out how…

Barn Conversion Roof Insulation

TLX Gold is the choice for barn conversions as it is quick and easy to install and enables a building to be weather tight quickly and effectively.Our recommended build up will depend on the induvial project. For
tlx gold single layer
 instance, if you barn is listed, then building regulations don’t apply, and a single layer of Gold, achieving a U value of 0.69w/m2k draped over the top of the rafters with a standard plasterboard below will be sufficient for maintaining a pleasant internal environment. If you want to retain the character of the roof, see our exposed rafter solution here.

If your renovation project is governed by building regulation requirements, generally a U value of 0.18w/m2k is required. To achieve this, a combination of a multifoil insulation with rigid insulation is the most efficient way of achieving the required U value whilst saving on internal space. Additional insulation can be fitted above the plasterboard, with 50mm battens fixed above and TLX Gold draped over the top of the battens. The most effective way to alter the U value is to vary the thickness of rigid insulation. However, the unventilated air gap between the material and the rigid insulation should be maintained to allow for the reflection of heat.

It is important to note that no single insulation material can achieve building regulations on their own, therefore, the use of a hybrid system combining a multifoil with rigid board is advisable.  

Barn Conversion Wall Insulation

Upgrading the insulation of solid masonry walls such as those generally found in old barns represents a real challenge to improvingmultifoil insulation used in a wall the energy efficiency of housing stock.Using external insulation would negatively impact the historic appearance of the building, thus internally lining the solid wall is the best option. Since multifoil insulation is an insulating vapour barrier, it can be used as an additional layer of insulation on the inner face of a solid wall, just behind the plasterboard. Secured with 38x38mm battens set crosswise to the interior cavity on timber studs or battens, it acts as a barrier on the warm side preventing water vapour from penetrating into the wall space behind, thus limiting the risk of condensation. To allow the material to perform to its optimum degree, a layer of static air is required behind it for the reflection of heat, which when combined with the multifoil enhances the R value of the air gap next to it. 

Meeting building regulation requirements

When installing insulation in any building, meeting building regulation requirements relies on a variety of factors. Below is a list of important considerations which can affect the U value of the structure:

Rafter depth – The deeper you rafter is, the more additional insulation can be fitted in-between them.

Rafter centers – Rafters are generally set at 400mm or 600mm apart. The further apart they are, the less thermal bridging will occur, therefore resulting in a lower U value.

How a multifoil is fitted – For instance, TLX Gold can be either draped or pulled taut and counter-battened. TLX Silver is secured with 38x38mm battens set crosswise. Incorrect fitting of a multifoil can lead to an inefficient insulation build-up.

The amount of additional insulation used – Adding a greater depth of insulation will increase the thermal performance.

The type of additional insulation used – Insulation materials have varying degrees of thermal resistance (Core R value.) Phenolic board has the greatest thermal resistance, whilst mineral wool is less so. Multifoil’s can be used in conjunction with a variety of insulation types, including mineral wool, PIR board and phenolic board. The resulting U value depends upon the thermal resistance value of the additional insulation used. For instance, phenolic board has a much greater thermal resistance than mineral wool and will therefore require less thickness to generate a lower U value.

Where ventilation is introduced – Where youintroduce ventilationis extremely important as it determines how effectively a multifoil works. The shiny surfaces of Silver and Gold reflect heat, therefore an unventilated air layer is required beside it.

Batten depth – It is important to get your batten depth correct as this will determine the depth of the air gap next to the multifoil.

The depth of unventilated air layers – The greater the depth of the unventilated air layer next to the multifoil, the more heat can be reflected against it and retained.

OurApproved solutions guide details a large variety of build-up recommendations, giving U value calculations based upon rafter/stud depth and the amount of additional insulation used. However, it your proposed build-up is not included, our team of technical scientists are on hand to help with bespoke calculations. We regularly work with architects and building control to design bespoke solutions for difficult to insulate buildings.

Further reading related to coverting older buildings using TLX can be found HERE

multifoil technical advice