GB2136042A - Wall repair system - Google Patents

Abstract

A system for repairing a property having an outer wall member (4) and an inner wall member (3), said wall members defining a cavity (2) therebetween and a plurality of upwardly extending support members being located in such cavity between the outer and inner wall members, herein a foamable material (1) is introduced into said cavity, said material being allowed to foam in situ to produce a foam which adheres to both the upwardly extending support members and to at least the outer wall member. The foamable resins are preferably based on unsaturated polyester resins and the system is particularly useful in the repair of Airey houses. <IMAGE>

Description

SPECIFICATION Property repair system The present invention relates to a system for the repair of a property. More particularly, the present invention is concerned with the repair of properties having an outside wall member and an inside wall member, said wall members defining a cavity therebetween and a plurality of upwardly extending support members being located in said cavity between said wall members. In a particularly preferred embodiment, the present invention provides a system for the repair of socalled Airey houses.

Airey houses are pre-cast concrete houses.

There are approximately 20,000 to 30,000 such pre-cast concrete houses in the United Kingdom which were built approximately 20 to 30 years ago. Such houses have an outer wall structure formed of a plurality of pre-cast concrete planks of approximately 3 ft. length which are attached to vertically extending concrete support members.

The planks are attached to the supp,ort members in staggered row formation. The inner wall member may be formed of any suitable material or lining, e.g. plasterboard.

A problem with such houses is that with the joints not being airtight or watertight, coupled with the fact that the staggering of the individual concrete planks means that there are both horizontal and vertical joints concerned, then water is able to penetrate into the cavity between the inner and outer wall members and consequently such water lies on the bottom of the cavity. The vertically extending support members are generally in the form of concrete posts or columns which have been reinforced with steel tubes. The posts or columns are generally of size 4" by 2" with a 1" diameter steel tube. When constructing such columns in many cases the steel tube extends right from the top to the bottom of the column. At the base where the column contacts the ground, water can penetrate under the concrete and attack the reinforcing tubes.The action of water on the steel tube causes such tube to expand which causes splitting of the concrete column. In 95% of damage to columns which have so far been investigated, cracks appear in the bottom portion of the concrete tube extending to a height of up to 6" to 12" from the base.

Accordingly, it is desired to repair such columns rather than replace them with fresh columns which would involve substantial time and effort.

It is therefore an object of the present invention to provide a system for repairing a property as defined above without having to replace the upwardly extending support members.

According to the present invention there is provided a system for repairing a property having an outer wall member and an inner wall member, said wall members defining a cavity therebetween and a plurality of upwardly extending support members being located in such cavity between the outer and inner wall members, wherein a foamable material is introduced into said cavity, said material being allowed to foam in situ to produce a foam which adheres to both the upwardly extending support members and to at least the outer wall member.

The foamable material utilised will be selected for the particular purpose intended to give desired strength and stability values to the property. In the case of Airey houses, it has been found preferable to use foamable resins based on unsaturated polyester resins manufactured and sold under the trade marks "MITEX", "LEGUPREN" and "LEG UVAL".

The upwardly extending, generally vertically extending, support members may be formed of any suitable material such as concrete, wood, steel or the like.

Whilst the present invention is applicable to all types of properties as defined above, the preferred embodiment is in relation to the repair of Airey houses. Accordingly, the following detailed description will be directed towards utilisation of the system of the present invention in repairing such houses, although it is to be understood that a similar type of procedure would be adopted in relation to the repair of other properties.

In order to extend the life of Airey houses, which suffer from damaged reinforced concrete columns, the present invention provides for the introduction of a foamable material into the cavity between the outer wall member formed from concrete panels and the inner wall member. The preferred foamable material utilised is based on unsaturated polyester resins which include as filler material, expanded clay, expanded glass, expanded slate or the like. For example, by utilising an expanded clay aggregate in a foam matrix, the foam itself having a very thick cell wall thickness, then the application of such foam to the cavity of an Airey house provides strength far in excess of other conventional foams.

When foamed in situ the foam has a very high adhesion to both the concrete support columns and the concrete panels thereby contributing stability to the building by in effect creating a ring beam and giving support to the concrete columns where damage and/or corrosion has taken place.

The system of the invention provides support for the columns and prevents further corrosion in the base of the column. The foamable material, when foamed in situ, has high adhesion to the concrete support columns and good compressive strength. This shows that the foam is capable of taking the anticipated loading of the column, even if the column is not in contact with the floor slab.

The system of the present invention ensures that the concrete support columns are sealed on the cavity faces to prevent further exposure of the column to air. Moreover, the steel reinforcing tubes may additionally be filled with an expanding grout to maintain a high pH should moisture be present from higher levels, and thereby prevent further carbonation of the concrete and/or corrosion of the reinforcement.

The carrying out of repairs to Airey houses utilising the system of the present invention results in the following outstanding characteristics.

1. Excellent adhesion to concrete.

2. Excellent thermal insulation.

3. Good loading bearing properties.

4. Good fire resistance.

5. Negligible shrinkage.

6. Ready penetration into effected areas.

7. Excellent resistance to weathering and corrosion.

8. Does not contain or set free any corrosive acids.

9. Completely resistant to fungus growth.

The method of application in accordance with the present invention is dependent upon the degree of deterioration but falls basically into two categories, i.e. either from the inside or from the outside. If the interior lining is suffering from dampness at the base then application is from the inside whilst replacing the plasterboard lining and D.P.M. Should no serious damage be present, then the application will be effected from the outside.

Whichever method is selected, the first procedure is to core holes in exterior or remove panels and then to clean the cavity and thoroughly inspect for serious defects to the base of any columns. If necessary column sections may be replaced by traditional methods.

Foaming from the inside is achieved by access through a horizontal gap left during the replacement of the interior linings. Foaming from the outside is by access through the coring of holes or the removal of a row of concrete panels, preferably the third row, replacing cores using epoxy adhesives, resuiting in higher strengths and more effective weather proofing than the original.

In either case, the foam is moulded with an integral D.P.M. on the top face sloping down from inside to outside terminating at the joint at the top of the second panel. New or existing D.P.M. is cut to overlap the top edge so that any moisture falling from the higher levels to the top face is projected to the outer face and has no possibility of so-called "pooling" as will be the case with the flat top of a traditionally grouted section. A completed section is shown in the accompanying drawing to indicate the manner in which the foam material (1) is located in the cavity (2), between the inside wall member (3) and the concrete panels (4) forming the outer wall member.

When filled from the inside the gap for filling is closed and the property is ready for redecoration.

When filled from outside, no damage is done to interior decoration except for possibly small marks caused by the temporary shuttering which is placed to restrain the foaming pressures. Where external panels are replaced, drill holes are filled with epoxy mortar coated with matching aggregate.

Having regard to the foaming characteristics of the foamable material utilised, calculations can be made as to the exact amount of materials necesary to produce foam to the desired height whilst maintaining sufficient strength.

Depending upon the type of resin utilised, the formulation thereof and temperature conditions, the foaming time can range from about 10 to 30 minutes. The gel time is generally from about 40 to 60 minutes. Thus, there is plenty of time for the materials to be inserted into the cavity before foaming takes place.

It can thus be seen that by utilising the system of the present invention the effective life of a property can be extended without the necessity of having to replace partially damaged support members by new members. Such system thereby enables the repair to be effected at a far more economic cost than would be the case if one where to replace damaged columns by fresh columns.

Whilst the invention has been specifically disclosed in relation to the repair of Airey houses, the system of the present invention is also applicable to the repair of Underdown houses, Boot houses, Parkinson houses, Winget houses, Reerna houses, Myton houses, Newland houses, Stoncrete houses, Stent houses, Dyke houses, C.C.C. houses, Woolaway houses, Orlit houses, Cornish Type 1 and 2 houses, Cornish flats and Unity houses and flats.

Claims (10)

1. A system for repairing a property having an outer wall member and an inner wall member, said wall members defining a cavity therebetween and a plurality of upwardly extending support members being located in such cavity between the outer and inner wall members, wherein a foamable material is introduced into said cavity, said material being allowed to foam in situ to produce a foam which adheres to both the upwardly extending support members and to at least the outer wall member.

2. A system as claimed in claim 1, in which the foamable material is a foamable resin based on an unsaturated polyester resin.

3. A system as claimed in claim 1 or 2, in which the foamable material includes expanded clay, expanded glass or expanded siate as filler material.

4. A system as claimed in claim 1, 2 or 3, in which the support members extend vertically upwards.

5. A system as claimed in any preceding claim, in which the support member is formed of concrete, wood or steel.

6. A system as claimed in any preceding claim, in which the property is an Airey house.

7. A system as claimed in any preceding claim, in which the foamable material is introduced into the cavity from the inside or from the outside of the property.

8. A system as claimed in any preceding claim, in which the foaming time for the foamable material is from 10 to 30 minutes.

9. A system as claimed in claim 8, in which the gel time is from 40 to 60 minutes.

10. A system for repairing a property, substantially as hereinbefore described and illustrated.