GB2117434A - Repairing airey houses - Google Patents

Abstract

A method of replacing the structural fabrication of an Airey house, comprises the following steps:- a) exposing, from the interior of the house, the existing concrete support columns in each external and party wall; b) from each corner of each external and party wall in turn, and over a part only of the wall, removing the existing columns and replacing them with steel columns; c) securing cross-bracing to the replacement steel columns; and d) removing the remaining existing columns positioned between the braced sets of replaced steel columns and replacing these removed columns with steel columns. <IMAGE>

Description

SPECIFICATION Structural fabrication for houses This invention relates to the structural fabrication of houses.

It is particularly concerned with replacing the structural fabrication of so-called "Airey" houses.

Airey houses are domestic dwelling houses in which reinforced concrete support columns carry external reinforced concrete cladding panels. Figures 1 and 2 of the accompanying drawings are sectional views showing, respectively, a typical external wall, and a typical external wall at a window opening. Figure 3 is a sectional ground floor plan view of a typical house.

As shown in these Figures, reinforced concrete support columns 1 have external horizontal reinforced concrete cladding panels 2 secured to them by copper wire ties 3. Internally the columns carry timber battens 4 to which a plasterboard dry lining 5 is secured.

Internally each support column 1 is reinforced by a mild steel tube 6. A major problem which is occurring is that carbonisation has taken place in the support columns, and in addition some columns have high chloride contents in the cement which results in accelerating structural deterioration of the columns. The carbonisation ailows moisture to pass through the concrete to the reinforcing steel tubes, and the resulting rusting of the tubes has a bursting effect on the concrete, leading to cracking and eventually to complete failure of the columns. The rusting action is heightened by the high chioride content, where present.

According to the present invention, there is provided a method of replacing the structural fabrication of an Airey house, comprising exposing, from the interior of the house, the existing concrete support columns in each external (and party if present) wall; from each corner of each such wall in turn and over a part only of the wall, removing the existing columns and replacing them with steel columns, removal and replacement being effected one column at a time; securing cross-bracing to the replacement steel columns; and removing the remaining existing columns positioned between the braced sets of replacement steel columns and replacing these removed columns with steel columns.

For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the remaining Figures of the accompanying drawings, in which: Figures 4, 5 and 6 correspond to Figures 1,2 and 3 discussed above, but show the house with the concrete columns replaced, Figures 7, 8 and 9 are internal elevations of a rear, a front and a gable end of the house with the concrete columns replaced, Figure 10 is a section on line X-X of Figure 9, Figure 4A is a detail taken on line A-A in Figure 4, Figure 5A is a detail taken on line B-B in Figure 5, Figure 7A is a detail taken on line C-C in Figure 7, Figure 9A is a detail taken on line D-D in Figure 9, and Figure 9B is a detail taken on line E-E in Figure 9A.

The first major step in replacing the structural fabrication of an Airey house of a construction such as illustrated in Figures 1,2 and 3 is to take-off carefully and store for re-use all timber skirting and architraves to external and party walls. Next all internal linings to external and party walls are removed and disposed of (linings to internal partition and spine walls are left in situ), as is the first floor ceiling and a 300 mm wide strip of ground flour ceiling adjacent the external and party walls. The support columns 1 are thus exposed for replacement.

It is imperative that only one full height column 1 at a time is removed and replaced, a full height column being the total column height from existing ground floor footings to eaves. Column removal and replacement is effected as follows, starting from a column at one corner. The first floor joist 7 adjacent this column is supported by a suitable prop. The existing copper ties 3 carried by this column are removed as are all bolted connections 8 at the first floor and the eaves. Utilising a suitable disc cutter the column is cut through at ground level, and the whole column (which is in upper and lower parts) is removed, by unbolting existing connections and with care being exercised as when the lower cut part is removed the remaining upper part has to be supported prior to its removal.The existing dowel connection at eaves level is cut away and the existing saddle connection 9 at the first floor joist is bent back to enable a replacement "R.H.S." (rectangular hollow section) steel column 10, which is also made up of lower and upper parts to be placed in position. To receive the foot of the replacement column, a base plate bracket 11 is bolted to the existing concrete ground floor. The foot of the lower part of the replacement column is welded to this bracket. At the top of the replacement column lower part a head 12 is bolted to the saddle connection 9.

The now-positioned lower replacement column part is secured to the cladding panels 2 utilising stainless steel wire ties. One end of each tie is tied to an existing hook on a cladding panel to one side of the column part, drawn around a softwood timber batten 13 that runs the length of the column part, and looped around the existing hook on the panel on the other side of the column part. The tie is then drawn back over the batten and tied securely to the first hook again. The tie is now tensioned by inserting, for example a nail of suitable length between the two strands of tie and revolving the nail to twist the strands over one another. This tensioning operation is effected on each side of the column, the nails being left in position, bearing on the adjacent panel, so as to retain the tension in the tie.

At the location of each tie there is a timber packing 14 between the column and the batten.

Once all the ties that are to pass around the lower column part in position, the upper column part is positioned. At its foot the upper column part is bolted to the head 12 of the lower column part, utilising plates 15, 16 respectively provided on the head 12 and the foot of the upper column part.

At its top, a head 17 of the upper column part carries a capping plate 18 which is secured to an existing timber wall plate 19. Existing eaves 20 are bolted to the head 17.

Working away from the first replaced column, columns are replaced in the manner just described until sufficient columns have been replaced for diagonal steel braces 21 and 22 (Figure 7) to be welded to the lower and upper column parts.

Once a fully braced set of replacement columns extending from one corner is in position, the procedure is repeated working away from another corner (or from the same corner in the opposite direction).

After all the eaves have braced sets of columns extending away therefrom in opposite direction, the remaining intermediate columns are replaced.

Variations on the above procedures occur at door and window openings as follows. At each door opening 23 (Figures 7 and 9) the existing full height jamb columns are removed and replaced one at a time as described above. On completion of the replacement jamb columns 1 OA, the (or one at a time for more than one) existing column above the existing door lintel is replaced by a new column 10B temporarily resting on top of the lintel. The existing lintel is now removed whilst supporting the new column(s) lOB and replaced with a steel lintel 24 which is bolted to the replacement jamb columns 10A. The (or each) column 10B above the lintel is then welded to the lintel.

At window openings 25 procedure is similar to that at door openings, with variations as follows.

After replacing the jamb columns one at a time the cladding panels above ground floor window openings are propped, and external shoring to the panel from ground floorto ground floor window cill level is provided. Also internal props to first floor joists and eaves wall plate over the columns to be replaced are provided. The existing full height window columns are removed one at a time and replaced by short columns extending from ground floor to ground floor window cill, from ground floor window head to first floor window cill, from ground floor to first floor window cill, and from ground floor window head to underside of wall plate of eaves level, as appropriate.A new lintel 26 is fixed above the head of each ground floor window whilst the replacement columns to be secured thereto are temporarily supported, and the short replacement columns thereabove are then welded to the replacement lintel.

New window cill trimmer beams 27 are positioned and the heads of short columns therebelow are bolted to these beams. In the present context by "short columns" is meant columns not extending the full height of the house. The cladding panels are secured with stainless steel ties as described above and external propping and shoring is removed.

It is to be noted that each window opening 25 after refurbishment is free of any structural members within the opening.

When column replacement has been completed, all internal horizontal and vertical joints between the cladding panels are sealed with a suitable sealant, plasterboardlinsulation laminate boarding 28 is se cured to the battens 13 to form a new internal dry lining, the ceilings are made good with plasterboard ceiling panels 29, and the skirting and architraves 30 are re-fitted.

Particular constructional details are illustrated as follows.

The base plate brackets 11 (Figures 4 and 7 for example) consist of two L-shaped cleats 11A welded to a base plate 11 B so that the column foot can be received between spaced apart upright flanges.

Each batten 13 is carried by its respective column, as as to be spaced therefrom by steel lugs 31 (Figures 4 and 5) welded to opposite sides of the column and projecting from the column to embrace therebetween the batten.

The head 12 of each lower column part is a flat plate that can be embraced by the existing saddle connection 9. The plates 15 are welded to the upper edges of respective head plates.

Above upper window openings (Figures 5A and 7 and 8) a new wooden lintel 32 is provided which is fixed to the existing wall plate by balstraps 33 and which is also supported by steel angle cleats 34 from the replacement jamb columns, and by further steel angle cleats 35 fixed to the existing eaves timber 36.

At the location of an existing stairwell trimmer beam 37 (Figures 7 and 7A) existing angle cleats 38 have their tops notched out, for example by burning away, to permit correct location of the plates 15 and 16, of the replacement column parts, which are to be bolted together. Also at this location the existing trimmer beam 37 is secured to the replacement columns by angle cleats 39, and in addition a further, steel, trimmer beam 40 is welded across the replacement columns.

Figure 4A shows that the replacement dry lining plasterboard 28 is cut away (at 28A) to accommodate the first floor joists, the voids so created being subsequently filled with an insulation material.

Above the ground floor window openings the upper column parts are secured to the lintels by base plate brackets 41 (Figure 5) similar to the brackets 11, the bracket 41 being welded to the columns and to the lintels.

In the gable wall (Figures 9 and 10) an existing timber trimmer 42 extending horizontally on either side of a chimney breast 43 is left in position, as are concrete columns that are behind the chimney breast. Steel angles 44 are secured between the heads of the replacement column lower parts and the trimmer 42.

In Figures 9A and 9B it is shown that in the gable and part wa l ls, the heads of the replacement column upper parts have welded to them plates 45 forming support fixings for the existing timber wall plate.

Web cleats 46 are incorporated in these welded connections.

The completed replacement support structure, consisting of the replacement columns and the diagonal bracings, is of sufficient stiffness in itself that, if necessary at some future date, the cladding panels could be removed and replaced with, for example, a brick outer skin, without effecting the stability of the house.

Claims (10)

1. A method of replacing the structural fabrication of an Airey house, comprising exposing, from the interior of the house, the existing concrete support columns in each external (and party if present) wall; from each corner of each such wall in turn and over a part only of the wall, removing the existing columns and replacing them with steel columns, removal and replacement being effected one column at a time; securing cross-bracing to the replacement steel columns; and removing the remaining existing columns positioned between the braced sets of replacement steel columns and replacing these removed columns with steel columns.

2. A method as claimed in claim 1, wherein the existing columns, which are in upper and lower parts, are removed by cutting away each lower column part at ground floor level and releasing the connections between the column and the remainder of the house, the lower column part followed by the upper column part then being removed; and wherein each replacement steel column, also in two parts, is made fast in position, lower part first, by securing the foot of the lower column part to the existing concrete floor, securing the head of the lower column part to an existing saddle connection, securing the existing exterior cladding panels to the lower column part, securing the foot of the upper column part to the head of the lower column part, securing the head of the upper column part to the existing structure, and securing the existing cladding pannels to the upper column part.

3. A method as claimed in claim 2, wherein the cladding panels are secured to the replacement columns utilising tie wires secured to existing fixings of the panels and passed around the replacement columns.

4. A method as claimed in claim 2 or 3, wherein at each door opening, after removal and replacement ofjamb columns, the (or each) existing column above the existing door lintel is replaced, whereafter this (or each such) replacement column is temporarily supported whilst the existing lintel is replaced and then the (or each) replacement column above the replacement lintel is secured to the replacement lintel.

5. A method as claimed in claim 2,3 or 4, wherein at each ground floor window opening, after removal and replacement of the jamb columns, the cladding panels above the openings are propped external shoring is provided to the panels from ground floor to window cill level, the first floor joists are temporarily propped and the existing concrete columns between the jamb columns are replaced by columns extending from ground floor to window cill, and from above the window head.

6. A method as claimed in claim 5, wherein after positioning the replacement columns above the window head, these columns are temporarily supported whilst the existing lintel is replaced, the replacement columns then being secured to the replacement lintel.

7. A method as claimed in claim 2,3 or 4, wherein at each first floor window opening where the house is a two storey house, after removal of the jamb columns, the cladding panels below the window cill are propped and/or shored, the existing eaves wall plate is temporarily propped, and the existing concrete columns between the jamb columns are replaced by columns extending from below to the window cill.

8. A method as claimed in claim 7, wherein a replacement lintel is provided above each first floor window opening, fixed to the existing wall plate, to the replacement jamb columns, and to the existing eaves timber.

9. A method as claimed in any one of the preceding claims, wherein wooden battens for receiving internal dry lining are secured to the replacement columns, spaced from the replacement columns.

10. A method of replacing the structural fabrication of an Airey house, substantially as hereinbefore described with reference to Figures 4 and 4A, 5 and 5A,6,7and7A,8,9and9Aand9B,and 10,ofthe accompanying drawings.