Totmonslow Farm, Tean

Structural Inspection of 2 no. Barns

For

Ian Ankers Architecture

Barn 1

Barn 2

By Steve Naylor BEng(Hons) CEng MIStructE

Date: 20/09/16

Introduction

This structural inspection concerns 2no. barns at Totmonslow Farm which form part

of the outbuildings to the main farm house dwelling. The report is provided for Ian

Ankers Architecture to form part of the Planning application to convert the barns in to

habitable dwellings.

Barn 1 is constructed from brick work and has overall plan dimension of

approximately 15.5m long and 8.5m wide. The barn has a pitched roof with an

approximate height to eaves of 2.5m and a ridge height of 6m. The barn is split in to

4 equal storage areas which are all open fronted to the north elevation, the 3 division

walls within the barn have large 600x600mm masonry piers to the front elevation, the

eastern division wall is a plain solid 9” (225mm) brick wall running front to back

between the front pier and the rear elevation wall, the central and western division

walls are also 9” solid walls, however, these incorporate 2 brick arches with central

600x600mm pier between, each arch is 1800mm wide and circa 4m high.

The roof structure comprises a pitched tiled roof supported by timber battens and

subsequent timber rafters at regular intervals, the rafters span on to 3 large random

sized timber purlins on each slope, the rear external elevation wall and a large timber

eaves beam running across the heads of the front elevation piers. The purlins are

supported by the gable walls and the 3no. full height internal division walls. No

gutters were present to either elevation, although signs of previous gutter fixings and

support brackets were present.

The external and internal walls are all approximately 9” (225mm) thick, the

foundations were not inspected, however, given the nature and age of the building it

is assumed that the foundation will consist of the wall corbelling out over a couple of

courses and founding at shallow depth.

There were no intermediate floors within the building, there were 2no small windows

within the rear elevation of the eastern most bay of the building. There was a

concrete ground floor slab present in the eastern bay, however, the other 3 bays had

no floor covering.

Barn 2 is constructed from masonry brick work and is ‘L’ shaped in plan and is split in to two distinct buildings, the long leg is a predominantly a 2 storey element approximately 24m long by 5.5m wide and the short leg is a single story building approximately 15m long by 6.5m wide. The 2 storey element is constructed using 13” (330mm) thick solid masonry brick work walls with intermediate load bearing cross walls. The first floor construction consisted of timber joists at regular intervals spanning the width of the building with a large timber beam at mid-span. This central beam was supported on the internal load bearing cross walls, gable wall and intermediate masonry pillars. The eastern most section of this section consisted of a double height space with no first floor. The roof construction of the 2 storey element consisted of large raised collar timber trusses with steel bar vertical and diagonal tension members supporting a single

purlin to each roof slope which in turn supported the rafters spaced at regular intervals and tiled roof. The ground floor was laid to random sections of concrete generally to falls to help drainage etc. The short leg section of the ‘L’ shaped building consisted of a single storey barn constructed in 13” (330mm) masonry walls with a concrete floor slab. The external ground slopes away considerably to the southern end of the building such that the ground level is circa 1.2m below the internal floor slab, therefore, this element of the external wall forms a retaining wall. The roof structure within this building is formed by a large braced king post truss and a large braced queen post truss, each supporting a single purlin along each slope of the roof. The purlins in turn are supporting the rafters spaced at regular intervals, and finished with tile battens and tiles. Inspection Summary This structural inspection report concerns the 2no. barn buildings at the above location; the inspection carried out was a visual inspection and did not involve any intrusive investigation or testing. Generally the barns are in a poor cosmetic condition, however, they currently serve their current purposes as general storage and housing animals. There are a number of structural issues that require attention to maintain the safety and use of the buildings, especially if the barn is to be converted in to a habitable dwelling.

Structural Design Philosophy The following assessment is based on the visual inspection only, and no calculations or analysis has been carried out. The barns are constructed with a traditional roof structure, the timber rafters carry the vertical loads due to gravity from the roof finishes via. flexural bending and shear action and transfer the loads to the timber purlins, which in turn transfer the loads via. flexural bending and shear action to the internal dividing load bearing walls, this load is transferred by compression of the wall structure to the foundations and subsequently to the founding ground strata below. Lateral loads arising from wind action are transferred from the walls via. flexural bending and shear action to the roof structure and lateral load bearing walls, this load is then transferred to the lateral walls that act as shear walls and transfer the loads to the foundations and subsequently the founding ground strata below.

Structure Condition No inspection was made of elements of the structure, which were unexposed or inaccessible and therefore it is not possible to report that such parts of the barns are free from defect. Barn 1 From a structural point of view the barn is generally in a poor cosmetic condition with some structural remedial measures required to maintain the safety and use of the building and particularly if the barn is to be converted in to a habitable dwelling space. The roof slopes are showing signs of undulation, and it can be clearly observed internally that most of the tile battens are suffering from rot with many broken and missing. The majority of the rafters appear to be in sound condition only several requiring replacement. The primary timber elements of large section purlins also are generally in good condition with just the odd isolated location of section loss and rot, where local replacement would be adequate. The western most timber eaves beam to barn is suffering from section loss and rot. None of the rafters or purlins are showing any significant signs of distortion or sagging. The masonry walls within barn 1 are probably the main area of concern, there, are large vertical cracks within the two arched dividing walls which support the purlins, these cracks appear to be historic in nature. The cracks are larger at the top, approx. 15mm in width narrowing to hairline at the top of the arches over a distance of about 1.5m. The front elevation piers are leaning over towards the east approximately 25mm over a 1m straight edge, therefore a total lean of approx. 75mm over the total height of the pier. The internal and gable walls were also leaning over local to the piers, however, by mid-way in to the barn they were vertical again. The remaining walls to the rear and rear elevation walls were plumb and level. There was a significant amount of vegetation and tree growth both on and adjacent to the western end of the barn, where the ground levels were also locally higher than the floor within the barn. No gutters were present to either the front or rear elevation at eaves level. The external brick work and mortar were heavily weathered with some water and frost damage present throughout.

Barn 2 From a structural point of view the barn is generally in a poor cosmetic condition with some structural remedial measures required to maintain the safety and use of the building and particularly if the barn is to be converted in to a habitable dwelling space. The roof slopes are showing signs of undulation, and it can be clearly observed internally that some of the tile battens are suffering from rot with many broken and missing. The majority of the rafters appear to be in sound condition only several requiring replacement. The primary timber elements of large section purlins and trusses also are generally in good condition with just the odd isolated location of section loss and rot, where local replacement would be adequate. The steel bar elements of the trusses are showing signs of heavy corrosion. Within the short leg of the ‘L’ shape the valley rafter was sagging considerably and appeared to be significantly undersized. The masonry walls within barn 2 generally 13” thick (330mm) and in general appear to be plumb and level with no evidence of any significant previous movement etc. There was a significant amount of vegetation and tree growth both on and adjacent to the western end of the barn, where the ground levels were also locally higher than the floor within the barn. The base of the external wall to the southern end of the short leg was exposed due to erosion and appeared to be built directly off sandstone rock, this rock has become weathered locally and has started to undermine the wall of the building, although this has not affected the wall stability at present. This end wall also forms a retaining wall as the external ground is approx. 1.2m below internal floor slab level. This wall appears satisfactory with no significant signs of distortion or rotation. The existing concrete floor slab is uneven and sloping with integrated channels to aid drainage etc. The timber floor boards to the first floor were in a very poor condition, such that it is not safe to use and should be completely closed off, many boards are missing and completely rotten through and many more very little strength. The primary and secondary timber elements supporting the floor appeared to be generally satisfactory with just minor isolated rot to joists etc. the main longitudinal beam was in good condition. The masonry piers supporting the primary beam appeared to be quite slender and poorly constructed. The gutters were in a poor state of repair throughout at eaves level. The external brick work and mortar were heavily weathered with some water and frost damage present throughout.

Conclusions and Recommendations

Overall the barns are in poor cosmetic condition, with some structural issues that require attention to maintain the use and safety of the buildings: Barn 1

1) The roof covering should be replaced, probably with something in keeping with the main dwelling to include roofing felt and insulation compliant with current building regulations.

2) The above will necessitate the replacement of all the timber roof rafters and

battens, some of the larger section purlins could remain and eaves beams could remain subject to calculation.

3) All the walls require complete re-pointing with some isolated brick

replacement.

4) The large cracks within the two internal dividing walls require stitching with possibly some minor taking down and re-building of the wall local to the cracks

5) The lean of the building to the front elevation is quite significant, however,

doesn’t appear to be ongoing. Given the extent some form of additional lateral stability should be provided to the front elevation in the form of a shear wall (buttressing) or a steel portal frame could be introduced to the opening at the front.

6) The existing ground floor should be removed and replaced with a new

concrete floor slab along with associated compacted stone, insulation and screed etc. compliant with current building regulations. The excavation depth required to achieve this may involve undermining the existing wall foundations, therefore, an allowance of some local/minor underpinning to the existing walls may be required.

7) The vegetation and tress adjacent to the western end of the building will require removing and the ground level reducing locally.

Barn 2

1) The roof covering should be replaced, probably with something in keeping with the main dwelling to include roofing felt and insulation compliant with current building regulations.

2) The above will necessitate the replacement of all the timber roof rafters and

battens, some of the larger section purlins could remain subject to calculation.

3) The timber valley rafter within the short leg of the ‘L’ will require replacing.

4) The steel bar elements to the roof trusses will require cleaning back to sound

material and re-painting.

5) The undermining of the wall to the southern elevation will require some local under pinning to maintain the stability of this section of wall.

6) The existing ground floor should be removed and replaced with a new

concrete floor slab along with associated compacted stone, insulation and screed etc. compliant with current building regulations. The excavation depth required to achieve this may involve undermining the existing wall foundations, therefore, an allowance of some local/minor underpinning to the existing walls may be required.

7) The timber floor boards to first floor level will require complete replacement.

8) Isolated timber joists will require replacement, however, the large majority could remain subject to calculation.

9) The masonry brick work will require completely re-pointing with some isolated brick replacement.

10) Masonry brick work columns supporting timber beam may require increasing in size.

In conclusion there doesn’t appear to be any ongoing significant movement or stability issues with either barn, the only slight concern is the existing lean to barn 1, however, there are simple solutions that could be included in any proposed development to satisfy the stability issues, either by introducing a shear wall within the front elevation to act as a buttress or incorporating a steel portal frame to the entrance to provide the enhanced lateral stability.

Barn 1 Photographs

Crack within internal dividing wall.

Vegetation and trees to western end of building

Frost and weather damage to masonry bricks and joints.

Front elevation of barn

Crack within dividing wall, majority of purlins appear satisfactory.

Barn 2 Photographs

Tied raised collar truss with steel bar tension members, steel work requires cleaning

back and re-painting. Note unsafe floor with ad hoc boards covering holes within

floor boards.

Timber valley member bowing significantly requires replacement.

Braced king post truss in good condition.

Braced queen post truss in good condition.

Wall appears to be built directly off sandstone rock at ground level, some weathering

and undermining has occurred.

Note weathering to brick work and mortar joints.

Timber joists and beam in generally god condition, note slender masonry columns

supporting timber beam.

Joists and beam in good condition, note missing and weak floor boards.