We have a large variety of construction types in the Peal District, spanning hundreds of years of materials development. Therefore the materials and methods of insulating the fabric need to take account of this variety.
You need to work up a list of priorities that apply to your home. – Jobs aways take longer and cost more than youinitially think! But most people surveyed consider the additional comfort to be worth the expense and disruption.
So list your jobs in order of energy savings, cost and impact.
The usual advice is to start with the quick jobs, such as draught proofing and loft insulation – working through towalls, floors and heating system controls. Maybe include double glazing if the windows need changinganyway.
DIY or contractors? Competent DIYers can tackle many of the items; draught proofing, loft insulation or internalwall cladding – if dry lined rather than a plaster finish. Theres lots of information online; choices of material andtechniques, calculators to estimate how eﬀective diﬀerent materials are, and costs. Do look at insulation manufacturers/suppliers websites. You can learn more about a material, most suitable applications, and techniquesfor fixing, plus loads of tech and health and safety data. SIG – Sheﬃeld Insulation Group have helpful staﬀ, andMarkovitz now have a specialist insulation depot.
Most commonly used insulation products are environmentally unfriendly, using lots of energy/ travel miles and complex chemistry in their make up. Fire retardancy is important for internal applications – seekmanufacturers advice.
More environmentally friendly alternatives are available, so seek them out. They are however generally moreexpensive, and require increased thicknesses for a given thermal transmittance. – Nick Parsons may be able to giveyou a list of these sorts of alternatives.
If going to a contractor check them out – references are essential for the types of work you may give them. Tradebody membership can be a mixed bag, unless governed by an independent body setting and enforcingstandards, with spot inspections.
Beware so called ‘surveyors’ employed by the contractor, its their job to convince you it needs doing and theirs is the best. Try to get independent advice.
The actual work involved for most jobs is not that complicated, usually just the traditional building skills. Its thematerials choice and specification bit that are crucial, plus good on site supervision to make sure materials areapplied correctly. A home energy specifier, independent of the contractor to draw up a schedule would repay itselfon larger jobs. If you’re prepared to do some of your own project management and DIY, then its possible to seeksuch as plasters and joiners to work with you and give a professional finish. You may also save a chunk of VAT!
Air circulation/draught proofing
Most modern windows and doors come with draught stripping incorporated – but worth checking its stillfunctioning. If not, then the ‘pin on’ strips are better than stick on types. Make sure door and window latches areworking properly. Don’t forget cat and letter flaps. Solid fuel fires need a supply of air to burn properly, larger firesneed an external air inlet – seek advice if in doubt.
First and second floor windows may be escape windows in case of fire- make sure they open freely after any work.Reducing air circulation can increase the risk of condensation, particularly on solid walls/floors in corners where aircirculation is poor.
Cold roofs/open lofts are where theres a void above a room. Easy to insulate, but may need to create access.300mm thickness of the loft roll type insulation is the usual material – rolled out between and over joists. Itsimportant to maintain ventilation throughout the void above the insulation layers. Don’t tuck it into the eaves toofar, at least a 50mm/2” gap should be maintained between the insulation and underside of roof tiles. Don’t forgetto insulate the loft hatch.
Take care with wiring or pipework- and make sure any water pipes and water storage tanks are fully insulated -the loft space will be much cooler.
Warm roofs – such as the sloping attic ceilings or dormer or other flat roofs. Needs special care. Will not usually beaccessible unless a re-plastering etc is planned. The usual standard is 150mm of such as Kingspan foil backed boardinsulation – many diﬀerent types so check.
When fixing up to a roof tiled area, leave at least 50mm between the insulation and the underside of tiles forcontinuity of ventilation across the roof spaces. In flat roofs a vapour barrier should be placed on the room side ofthe insulation before fixing plasterboards. This is sometimes incorporated in the insulation so check. This is toprevent moisture laden warmer air penetrating through the ceiling insulation etc, and then condensing on theunderside of the flat roof surface – which could be close to freezing – it can then drip back down into the room!
If the room is not undergoing full replastering, or the loft over the ceiling is inaccessible, then a layer ofinsulation can be screwed to the plastered inside – at least 75mm, but more if space allows – you’ll need todiscover where the joist are for fixing. Then cover with plasterboard and skim, or dry line – insulated plasterboard is useful, but more expensive.
Before drilling or screwing into any covered surface, make sure pipes and cables are not concealed.
Cavity Insulation. The cavity, 50-100mm, is designed to prevent moisture transmitting through the wall. There areguidelines governing cavity fill, but don’t rely on a cavity wall insulation firms
‘surveyor’ to say your home is suitable for their method. Ask your local councils area building control oﬃcer foradvice – he/she will know your area well, and the exposure ratings/construction materials of your type of house. -Permission may be required to fully fill the cavity. If having an installer, make sure they maintain ventilation at eavesand below dpc air grates. Properly installed its eﬀective and invisible.
External wall Insulation. Stick on/screw on insulated panels, 50-100mm thick, which are given a specialrender/dash finish. – Existing render may need hacking oﬀ. Altering the external appearance may need plannersapproval. Similar caveats as for cavity wall insulation. May need scaﬀold and window cill, gutters/downpipesalteration. If you’re re-rendering your home, then its an excellent method – but needs a specialist firm. Expect tobudget £90-150/m2.
Very disruptive unless re-wire and re-decoration is planned. Needs between 50-100mm to be cost eﬀective giventhe costs of ancillary work. Usual material is again the Kingspan phenolic foil backed board insulation in 8’x4’ sheets. The sides of window openings are usually impossible to treat and may then be prone to condensation by coldbridging.
Skirtings, coving, window boards, sockets, light switches, radiators will need specialist attention. As with all theinsulation boards, try to get the special insulating fixings which prevent cold bridging.
Actual board fixing could be DIY. All wall coverings and loose plaster needs removing, well adhered plaster can beleft but scarified. Use an appropriate dry lining adhesive in dabs to stick the boards plumb and level, then when setfix with appropriate fixings securely to the wall through the adhesive dabs – do not rely on glue alone!
Where walls are severely uneven or out of plumb, or damp, then dry lining with metal stud partition is veryeﬀective. A independent stud wall is created and tied back to the existing walls with straps. – 50-100mm thick thisis then filled with insulation, but the surface must be lined with at least 25mm insulation backed plasterboard toprevent condensation cold bridging on the steel studs. Very eﬀective for damp walls, or loose and irregularstonework. British Gypsum have guidelines for specifying and fixing.
If they need replacing anyway, then a good quality double or triple glazed system is eﬀective, and will increaseroom comfort levels by reducing convection driven air circulation. Listed buildings may require a secondary system,so as not to not to change the external appearance.
All window replacements should be dealt with by a registered installer, or you will need building control approval- so amounts of light, ventilation, toughened glazing and appropriate escape windows are provided to buildingregs.
Larger glazed areas can be a problem for heat loss – even thermally eﬃcient triple glazing is not a good insulator. Bi-fold/patio doors etc, can be eﬀectively insulated at night or in winter, by insulated hinged shutters on the inside. These can be hinged back or removed and stored during summer. A simple construction of say 50mm Kingspan sandwiched between 5mm plywood skins in a timber frame. Do not use cheap expended polystyrene in any roomapplications due to its dangers during fire.
If underfloor access is good, then 100mm Kingspan fixed between ground floor joist and tight up to underside offloor-covering is ideal.
There needs to be at least 150mm clear ventilation space under floor joists, also make sure any external air grates are clear for ventilation. Good underfloor ventilation is essential to prevent dry- rot establishing. Care needed around pipes and cables, also make sure all pipes are well lagged.
Very disruptive as ideally 100mm of special flooring type insulation needs to be incorporated without altering existing floor levels too much. Wet underfloor heating could make this worthwhile, so air or ground sourceheat pumps have the ideal form of room wide low
temperature circulation. Alternatively a special concrete topping of at least 100mm can be applied for polishing.
Either a liquid self levelling screed 40-60mm can be applied over the insulation and damp membranes for tilingetc, or a ‘floating’ type floor. This is such as flooring t and g chipboard sheets glued together, for subsequentcarpet or decorative timber covering. Special insulating
sheets are available which have grooves for wet underfloor heating pipes- which are then covered by the chipboardlayer.
Heating/Ventilation Systems and Controls
Beyond the scope of this leaflet. However, if you are considering air or ground source heat pumps, these systems operate at lower temperatures than fossil fuel fired boilers and so good insulation will be required, notonly for eﬃciency, but also can be a pre-requisite of any grants.
I’ve mentioned Kingspan products, many others are available and costs can vary, do check the manufacturersspecification for your particular application.