What should I do if I have not received a Certificate of Compliance?2018-12-18T23:35:43+00:00

If you have had cavity wall insulation fitted retrospectively and have not received a Certificate of compliance within 30 days of completion you should contact the Cavity Wall Insulation Self Certification Scheme operator, CIGA, etc., or your installer as appropriate. Alternatively, your Local authority building control department may be able to assist.

Could failure to submit a building notice affect the sale of my house?2018-12-18T23:35:25+00:00

Building owners should always check that a building notice has been submitted. If the work has not been notified to a Building Control Body the Local Authority will have no record that the work complies with Building Regulations. This will be important when you come to sell your home as you may be asked to provide the certificate of compliance with the Building Regulations.

Do cavity wall insulation installers have to submit a building notice?2018-12-18T23:35:03+00:00

CIGA requires installation member companies are responsible for ensuring;

  • In England & Wales, the installer must submit a building notice to the Building Control Department of the appropriate Local Authority at least 48 hours before installing CWI. Further, the installation must not commence unless the building notice has been submitted. Failure to submit an appropriate Building Notice is a criminal offence.
  • Installation details are provided to the Scheme Operators (CIGA),who will in turn notify the Local Authority
  • Self Certification information is provided to Local Authorities.
  • Details of installations are provided to the BBA for the purposes of Assessment and Surveillance.

The National Insulation Association (NIA) Code of Professional Practice also requires:

“Our members must follow relevant British Board of Agrement (BBA) or British Standards specifications, product or system supplier’s recommendations and Building Regulations in the case of cavity-wall or solid wall insulation, and they must, under Building Regulations, send notice of the work to the Local Authority.”

What is the Cavity Wall Insulation Self-Certification Scheme (CWIS)?2018-12-18T23:34:42+00:00

Where an Approved product is used strictly in accordance with the requirements of the BBA Agrement Certificate and can be awarded a CIGA Guarantee it can be notified via the Cavity Wall Insulation Self Certification (CWISC) scheme.

The Cavity Wall Insulation Self-Certification Scheme (CWIS) covering the retrofit installation of cavity wall insulation in suitable buildings in England and Wales is operated and administered by the Cavity Insulation Guarantee Agency (CIGA), in association with the British Board of Agrément (BBA). The Department of Communities and Local Government (DCLG) is responsible for the approval, monitoring and quality assurance of the scheme and requires scheme operators to gain United Kingdom Accreditation Service (UKAS) accreditation.

The Cavity Wall Insulation Self Certification Scheme requires the scheme operators, CIGA, to:

  • retain records of installations completed under the Scheme
  • issue certificates of compliance to consumers, and
  • provide details of installations to Local Authorities.
What information should accompany a building notice?2018-12-18T23:34:15+00:00

The building notice shall be accompanied by a statement including:

  • the name and type of insulating material to be used;
  • whether or not the insulating material is approved by the British Board of Agrement (BBA), BRE, LABC or conforms to a British Standard specification;
  • whether or not the installer is a person who is the subject of a British Standards Institution (BSI) Certificate of Registration or has been approved by the British Board of Agrement (BBA) for the installation of that material.


Do I need a building notice for retrofit cavity wall insulation?2018-12-18T23:33:47+00:00

The installation of cavity wall insulation in both new and, when fitted retrospectively, in existing buildings is subject to the Building Regulations, and to comply with the Building Regulations a notice must be given to the relevant Building Control Office.

A Building Regulations submission can either be in the form of a notification from a competent persons scheme, or an appropriate Building Notice made to the Local Authority if the work is not covered by a competent person scheme.

Can children’s education be affected by cold damp homes?2018-12-18T23:33:19+00:00

Children’s education can be affected. Cold and damp homes can increase the time it takes to get over an illness which could mean longer absences from school.

Homes with damp, wet, or saturated walls cost more to heat. When standard (fibre, bead) insulation materials become wet they lose their thermal performance benefit, damp walls conduct heat more readily than a dry wall, and will increase the homeowner’s heating bills. For many families already living in fuel poverty it is often a choice between heating their home and buying food to eat and this will add to their misery and impact on their well-being.

Homeowners will also incur misery and high financial costs associated with major remedial works (removal of bricks, plaster, redecoration, etc), and prolonged disturbance in connection with drying out of their homes over many months.

Are my children at risk from living in cold damp homes?2018-12-18T23:32:57+00:00

World Health Organisation report, Children Living In Homes With Problems Of Damp, Fact Sheet 3.5, 2009 states:

Children are particularly susceptible to the health effects of damp, which include respiratory disorders such as irritation of the respiratory tract, allergies and exacerbation of asthma.

Excess moisture leads – on almost all indoor materials – to growth of microbes such as moulds, fungi and bacteria, which subsequently emit spores, cells, fragments and volatile organic compounds into the indoor air. Moreover, dampness initiates chemical and/or biological degradation of materials, which also causes pollution of the indoor air. Exposure to microbial contaminants is clinically associated with respiratory symptoms, allergies, asthma and immunological reactions. Dampness has therefore been suggested to be a strong and consistent indicator of risk for asthma and respiratory symptoms such as cough and wheeze.

What health issues are there with cold homes?2018-12-18T23:32:32+00:00

Insulated homes are warmer and more comfortable. They cost less to heat, and are kinder to the environment.

Living in a cold, damp environment can exacerbate health problems such as:

  • influenza,
  • strokes, and
  • heart disease.

Cold and damp homes promote the:

  • growth of fungi,
  • mould, and
  • dust mites

which are linked to asthma and other respiratory conditions.


Where can I find advice concerning use of cavity wall insulation in flood risk areas?2018-12-18T23:31:39+00:00

The Association of British Insurers (ABI) highlighted the serious flood risk facing Communities in 2001 and advised that only closed cell insulation should be used in flood risk areas.

Planning Advice Note PAN 69 (Planning and Building Standards Advice on Flooding) recommends that closed cell insulation is most suitable for construction where flood risk is an issue. Mineral fibre and other absorptive insulating materials will retain water and can lose their insulating properties or disintegrate over time. (Scottish Executive, 2004).

DEFRA, DCLG and the Environment Agency (Improving the flood performance of new buildings) report published May 2007 advised, rigid closed cell (polyurethane) PUR foam is also shown to be the best performing material when installed into cavity walls. The report states “Cavity insulation should preferably incorporate rigid closed cell materials as these retain integrity and have low moisture take-up.”

What is the cost of flood repair?2018-12-18T23:30:33+00:00

The annual cost of flood damage in England alone is reported to be more than £1.1bn. The lives of flood victims can be disrupted for months or sometimes years. The 2007 floods in Hull for example, resulted in approximately 17,000 homes affected and 30,000 made homeless with an average insurance bill of £50,000.

Is standard cavity wall insulation (fibre, bead) suitable in flood risk areas?2018-12-18T23:30:09+00:00

Flood waters can penetrate unprotected cavity walls and cause major damage to the outer walls, cavity wall ties, standard cavity wall insulation materials, plaster, electrical appliances, furnishings and decorations. The cost of removal and/or drying out of saturated standard insulation materials can be exorbitant and highly disruptive.

Flood insurance is now a major concern for many thousands of homeowners in flood risk areas. Homeowners in flood risk areas are often faced with hefty premiums and huge excesses – even when they have never been flooded.

How many floods are there each year?2018-12-18T23:29:46+00:00

For over a decade there has been at least one serious flood a year in the UK, and experts are now predicting the impacts of climate change and rising sea levels could increase the intensity and frequency of inland, coastal, and flash floods over the coming years.

How many homes are at risk of flooding?2018-12-18T23:29:29+00:00

Of the circa 30 million properties in Great Britain 6.3 million, or one in five, are at risk of flooding from rivers, the sea or surface water so there’s a high probability one of these properties is your home or business.

Where can I find out more about dry rot and wet rot?2018-12-18T23:29:03+00:00

For further information refer to:

How can I identify wet rot?2018-12-18T23:28:25+00:00

The most common coniophora puteana and coniophora cerebella (cellar fungus) are only attracted to very damp wood or plaster and unlike dry rot, remains confined to the wet area only.

Decayed wood resembles wood attacked by dry rot and if left untreated can seriously harm the structural integrity of the timbers within a building and prove hazardous.

Paxillus panuoides is similar to cellar fungus with yellowish or violet fibrous growth and a small mushroom like fruit body with gills on the underside. The wood is discoloured reddish-brown.

White rots darken at first and later become much lighter in colour and lint-like. Phellinus megalaporous (or cryptarum) has often caused serious damage to oak in old buildings.

Wood with wet rot has a typically soft and spongy feel than surrounding healthy wood.

What is wet rot and can it cause damage?2018-12-18T23:27:37+00:00

The most common wet rots found in buildings are:

  • Coniophora puteana and Coniophora cerebella)
  • Paxillus panuoides
  • White rots

Wet rot is not as difficult to eradicate as dry rot but occurs more often and can cause serious damage if left untreated.

How can I identify dry rot?2018-12-18T23:27:15+00:00

In damp conditions it has the appearance of a cotton-wool-like mass and in drier conditions it has a grey skin with occasional patches of yellow or lilac areas. The fruit bodies are marked by wide shallow pores and rusty-red spores.

Its spores travel quickly over surfaces and through minute cracks in brickwork, plaster and other materials which provide no nourishment. Decayed wood is brown and divided by deep cracks along and across the grain and is dry and powdery.

What is dry rot and can it cause damage?2018-12-18T23:26:29+00:00

Dry rot (Merulius Serpula lacrymans) fungi are vigorous strand producers, spread extensively and can reduce structural beams, joists and timbers to crumbling hazardous elements causing serious damage to structures, and is more difficult to eradicate than wet rots.

It is generally found in wood which has been slowly dampened, from contact with damp brickwork, in very stable conditions, and thrives in warm, unventilated conditions. It is often found in the underside of timber floors, beneath stairs, behind skirting boards and in roof trusses.

Within a matter of months dry rot can cause serious harm to the structural integrity of the timbers within a building so if you suspect it may be present it is vital that you act immediately to eradicate it.

Do dry rot and wet rot need moisture?2018-12-18T23:26:05+00:00

Both dry rot and wet rot need moisture and can cause serious structural damage to a home. The optimum moisture content for the growth of both dry rot and wet rot is 30% – 40%, but dry rot cannot infect very damp timbers.

Why is the cavity wall insulation wet?2019-01-14T19:15:48+00:00

Cavity wall construction generally consists of two leaves of masonry, an outer leaf (of facing brickwork, natural stone, blockwork with render, etc) and an inner leaf of brickwork or blockwork separated by a nominal 50mm wide cavity. Recent practice has been to fill the cavity with insulation materials to reduce heating bills and carbon omissions.

Published guidance by the Building Research Establishment (BRE) says that there is an increased risk of rain penetration if a cavity is fully filled with insulation. Rainwater may penetrate the outer leaf of a cavity wall, bridge the cavity via the insulation material and transfer moisture to internal walls, causing damp and consequent mould.

If you think your home is suffering from wind driven rain penetration, condensation or rising damp you should seek advice from a reputable expert.

How do I find out if the insulation measure is suited to stone-built homes?2018-12-18T23:23:49+00:00

The reader should check the current Ofgem listing of Appropriate Guarantees for cavity wall insulation measures suited for use in stone-built homes with uneven cavities, including where these have stone ties, where there are no damp proof courses, and where there are failed wall ties.

What are Ashlar Coursed Natural Stone?2018-12-18T23:23:23+00:00

A 300 mm course height is typical for ashlar coursed natural stone and provides a traditional appearance to the stonework and is traditionally designed with nominal 5 mm wide joints.

Is cavity wall insulation suitable for use in stone-built homes with stone wall-ties?2018-12-18T23:22:20+00:00

Standard (fibre, bead) cavity wall insulation (CWI) measures are unsuitable for use in stone-built homes with uneven width cavities (including where the walls have through stone ties).

Do stone wall-ties cause thermal bridges?2018-12-18T23:21:55+00:00

Thermal bridges exist in all early cavity wall constructions particularly when the leaves are tied together with stones. Cavities closed by brick or block masonry at the top of walls (capped cavities) and around windows and doors provide a direct path where heat can be easily conducted across the cavity and condensation may occur on internal surfaces of walls. Through stone wall-ties also provide a cold bridge from the outer wall to the inner wall, and condensation may occur at these points on the inside wall of the house.

Do stone wall-ties cause rainwater ingress?2018-12-18T23:21:32+00:00

The natural stones used in the construction of traditional stone-built homes are themselves able to resist wind driven rain penetration but some water will inevitably penetrate through the lime mortar joints of the stone outer leaf of the cavity wall and may eventually become saturated. The degree of saturation depends largely on the intensity and duration of the wind and rain. Stone built homes located in severe or very severe wind driven rain exposure conditions may be vulnerable to prolonged periods of saturation, and the stone ties may provide a direct path for possible rain water penetration into the inner leaf

What are through stone wall-ties?2018-12-18T23:20:46+00:00

Wall ties are an essential structural element to any building with a cavity wall irrespective if the wall is a traditional coursed stone, random rubble filled stone or brick-built cavity wall.

Photo: Through stone wall-tie

 Natural coursed stone built walls are built course by course to the desired height and at strategic locations “stone ties” or “through stones” are placed perpendicular to span across the external leaf, the cavity and the inner leaf of the wall. These effectively “tie” the leaves of the wall together, and greatly increase the overall strength of the wall. See photo above.

Traditional coursed natural stone cavity wall properties2018-12-18T23:19:27+00:00

The rough stone blocks from the quarry is cut to rectangular or square format of nominal 100mm height which produces the dimensioned shape to make them suitable for incorporation into “stretcher bond course” cavity wall construction, the exposed weather face and inner cavity face are left uncut which results in built in uneven width cavities.

In traditional “stretcher bond” coursed natural cavity wall stone properties the stone element is used as the outer leaf, being supported and backed by an internal load bearing inner leaf of stone or brickwork which may be tied together with through stone ties or wrought iron ties which span both the inner and outer leaves of the cavity wall.

Wrought iron ties are susceptible to corrosion and should be checked and replaced where necessary.

How can I tell the difference between random rubble filled solid wall natural stone and “stretcher bond” coursed natural stone-built homes?2018-12-18T23:16:52+00:00

Traditional random natural stone rubble filled walled properties (shown below)


Traditionally-built random (non-uniform shape) natural stone rubble filled walls (around 600 mm or more in thickness) are permeable to water and rely on their thickness to prevent moisture transfer to the inside surface and carry all the structural loads, unlike coursed natural stone non-rubble filled cavity wall properties where rainwater ingress to the inner leaf is prevented by the cavity and the structural loads are carried on the inner leaf of stone or brickwork.


What causes cracks in masonry walls?2018-12-18T23:15:10+00:00

Cracks in brick or stone walls can be caused by a number of factors including wall-tie corrosion and subsidence or foundation movement. Changes in the ground conditions under and around a house can cause it to move slightly, which can lead to cracks developing in the walls.

It should be stressed that the assessment needed to properly classify cracking in housing requires several factors to be taken into consideration, including whether the widths of the cracks are increasing with time. An expert building professional should always be consulted when carrying out any assessment of cracking in masonry walls prior to installation of external wall insulation or cavity wall insulation measures.

Will wall-tie corrosion affect my mortgage application?2018-12-18T23:14:43+00:00

Wall-tie corrosion is also a growing problem when applying for a mortgage. Mortgage valuation surveyors are increasingly recommending that wall-ties should be inspected as a condition of a mortgage advance and any signs of defective, corroded or missing wall ties may cause delays when homes are put on the market.

Is it costly to replace wall ties?2018-12-18T23:14:14+00:00

Replacing wall-ties is a costly, disruptive and time-consuming process, involving cutting out dozens of individual bricks from the outer leaf and replacing the affected wall-ties.

Do wall ties corrode?2018-12-18T23:14:14+00:00

South and west facing elevations of buildings, and buildings in coastal locations subject to severe wind driven rain exposure conditions and walls subjected to flooding which remain wet for prolonged periods of time are particularly vulnerable to wall-tie corrosion.

What do wall ties do?2019-01-14T19:06:44+00:00

Wall-ties are an essential element for ensuring the structural stability of the outer leaf, securing the weather protecting brickwork facade to the main body of the building at regular intervals and are usually manufactured from twist galvanised steel or wire ties spaced at 900mm apart horizontally and 450mm vertically.

The wall-ties are responsible for transferring the live and imposed wind suction loads across the cavity, enabling load-sharing by both the inner and outer leaves of the wall, and to prevent detachment or collapse of the outer leaf of masonry.

What is a cavity wall?2018-12-18T23:14:14+00:00

Cavity walls typically consist of an outer leaf of 100mm thick masonry brickwork, a nominal 50mm wide cavity, and an inner leaf of 100mm thick blockwork. The outer and inner leaves are tied together with wall-ties which are installed during construction.

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