NB: Please read this in conjunction with ‘EXTERNAL FABRIC’. Overlaps and boundary issues are inevitable! The information offered principally concerns insulation.
See References and Sources for acknowledgements of information contained. Those marked with an asterisk (*) are available as a hard copy for reference in Newington Library.
HEATING REGIMES AND EQUIPMENT
NB: See also ‘Services’
Before considering any upgrade to building fabric, it is important to first ensure that space heating equipment such as boilers and radiators are being used efficiently. Studies have shown that the effective use of such equipment can have a larger impact on reducing emissions and fuel consumption than fabric interventions. Where central heating is used this should be fitted with proper controls and these should be well understood by the building owner or occupier.
REFERENCES AND SOURCES
Inform Guide: Improving Energy Efficiency in Traditional Buildings *
FLOORS
TIMBER FLOORS
Underneath timber floors at ground level, often called a suspended timber floor, there may be sufficient crawl space to allow insulation to be installed on the underside. However in most circumstances there is not enough space and insulation needs to be installed from above. If it proves necessary to lift the boards to install the insulation this should be done with care to avoid damage to the original fabric, and may be deemed not worth the risk. If floorboards are lifted with care most can be re-laid, with some new boards typically being needed to make good any damage. An experienced joiner can sometimes remove every 5th or 6th board, reducing disruption and damage. However the cost of this work should be weighed with the benefit from insulation being installed.
As with loft insulation a material which allows some degree of moisture movement should be used, whether it’s installed from above or below. Laying non-permeable insulating board on top of a timber floor will inhibit water vapour movement, and may give rise to timber decay.
SOLID FLAGSTONE FLOORS
These should generally be left in situ as lifting them may cause damage. However, where a flagstone floor requires to be lifted for other reasons it may be worth considering laying an insulated lime concrete floor under the flags. There are considerable benefits in insulating new concrete flooring with a proprietary insulation, where original floor finishes have been lost.
REFERENCES AND SOURCES:
Inform Guide: Improving Energy Efficiency in Traditional Buildings *
INTERNAL WALLS
Generally in Scotland a dry masonry wall of around 600mm in thickness will provide a reasonable thermal barrier, although current thermal assessments tend to consider them as thermally poor. Where lath and plaster remains in situ on the internal face of the wall its removal is not recommended.
Internal insulation that requires the removal of existing wall linings is only appropriate where there are no existing historic and original materials. Examples of options are:
- Putting material behind the existing lath and plaster. Bonded polystyrene bead or cellulose fibre can be blown behind the existing wall finish after some re-wiring work has taken place for electrical safety reasons.
- Icynene sprayed behind lath and plaster could be considered, but its long-term efficacy of has not yet been evidenced.
- Thermal wallpaper or a thin (10mm) aerogel insulation applied as a wall covering.
- Historic Environment Scotland’s tests have shown, however, that lath and plaster with a void behind provides a degree of insulation in itself, and it may be better not to intervene where such lath and plaster is still in place.
Where a more significant upgrade is required there are a range of insulation types which can be applied to walls internally:
- The board type insulation is fitted between existing or new timber strapping and can be finished with a skim coat of plaster. Materials such as blown cellulose is sprayed on damp and finished with a board being placed over the material.
- All the materials that have been tested give significant improvement to the thermal performance of the building.
Whatever materials are selected, it is important to ensure that they have a good degree of vapour permeability and do not incorporate or create a vapour barrier which could lead to a build-up of moisture in a wall. Good detailing at junctions with windows/doors/floors and ceilings is also crucial to the success of such an installation.
REFERENCES AND SOURCES:
Inform Guide: Improving Energy Efficiency in Traditional Buildings *
CHIMNEY BALLOONS
Even when no fire is lit, ventilation is an important function of the chimney system in a traditional structure. The rising air in the chimney draws new air into the room from under the floor and behind plastered surfaces, keeping void spaces and hidden areas dry. Flues should not be closed off. To reduce draughts from unused flues they should only be temporarily closed off with a chimney balloon, while still allowing some trickle ventilation to occur. Chimney balloons are available at good hardware shops and can easily be fitted by the owner/occupier.
REFERENCES AND SOURCES:
Inform Guide: Ventilation in Traditional Houses | Hist Env Scotland *
How to draught-proof your chimney – Energy Saving Trust
DRAUGHT-PROOFING
Controlled ventilation helps reduce condensation and damp, by letting fresh air in when needed. Draughts, however, are uncontrolled: they let in too much cold air and waste too much heat. Removing draughts can lead to reductions in the heating levels required and can also be helpful in reducing dust and noise. Draughts at junctions between floors and walls can often go unnoticed, but have a considerable effect on the energy required to heat the building.
Old houses are typically draughty and air tightness testing can pinpoint holes/gaps in the fabric of the building. EALA (a social enterprise Conservation Architecture and Chartered Building Surveying practice) recommends a blower door fan to increase the pressure in each room, a smoke pencil to identify the draughts and to direct a joiner sealing up gaps. They have worked with Luths (https://www.luths-services.com/) who will help domestic clients. Getting the balance right is essential, but will inevitably be different for each property depending on building fabric and occupant use.
Sash windows were designed to allow some air flow into a room, but not to be draughty. Draught-proofing can reduce air-leakage and the feeling of cold within a building. It is relatively simple to draught proof a window using silicone sealant, foam-backed strips or by inserting brush strips into the baton rods and meeting rails.
REFERENCES AND SOURCES
Short Guide: Maintaining Your Home | Historic Environment Scotland *
Inform Guide: Ventilation in Traditional Houses | Hist Env Scotland *
A helpful guide to draught-proofing – Energy Saving Trust
A local resident has kindly shared this link showing personal experience of retrofit.