AHBSS, Whitley Bay (2025)

22/08/2025

Alan Holmes Building Surveying sponsoring Rockcliff Whitley Bay Beer Festival again this year. Lloyd Holmes

02/07/2024

Temperature variations and the influence of synesthetic turf on subsoils.

It is commonly known that the upper 600mm of ground is susceptible to seasonal moisture variations. Since UK Building Regulation introduction in 1965, foundations were recommended to be at a minimum depth of 600mm below ground level to avoid seasonal variations, of shrinkage, heave (swelling) and frost expansion. The water content in these upper layers is significantly influenced by climatic and environmental factors and is generally termed the zone of seasonal fluctuations or active zone. This is particularly relevant when foundations were laid on clay sub soils. And today, it would be recommend to be no less than 900mm dep in a clay sub soil and deeper where there is vegetation within a theoretic root-affecting zone of influence.

Clay particles are very small and their shape is determined by the arrangement of the thin crystal lattice layers that they form, with many other elements which can become incorporated into the clay mineral structure (hydrogen, sodium, calcium, magnesium, sulphur). The mechanism by which these molecules become attached to each other is called adsorption. The clay mineral montmorillonite, part of the smectite family, can adsorb very large amounts of water molecules between its clay sheets, and therefore has a large shrink–swell potential.

When water is removed, by water demand from vegetation, evaporation or gravitational forces, the water between the clay sheets is released, causing the overall volume of the soil to decrease, or shrink.

Shrinkage by evaporation is similarly accompanied by a reduction in water pressure and development of negative capillary pressures. The seasonal volumetric behaviour of a desiccated soil is complex and this increases with severity of the shrinkage phenomena.

The term ‘Active Zone’ can have different meanings. Nelson et al. (2001) provide four definitions for clarity:
1. Active Zone: The zone of soil that contributes to soil expansion at any particular time
2. Zone of Seasonal moisture fluctuation: The zone in which water content change due to climatic changes at the ground surface.
3. Depth of wetting: The depth to which water contents have increased due to the introduction of water from external sources
4. Depth of potential heave: the depth at which the overburden vertical stress equals or
exceeds the swelling pressure of the soil. This is the maximum depth of the active zone.

We (AHBSS Ltd) have been involved defending a client from accusation that a mature tree has recently caused clay shrinkage problems to a nearby house.

To discount all other possible factors (before felling the perfectly healthy tree) we believe that all factors must be considered. These other factors including: evaporation and volumetric changes in the ‘Active Zone’.

In our case study, the offshoot of the adjacent Victorian property has a brick footing bearing onto a sandy clay only 250mm below ground level (yes! 250mm or three course of brick below ground). In our opinion well with the ‘Zone of Seasonal moisture fluctuation’ and well within an ‘Active Zone’ for evaporation shrinkage.

The reported cracking in the offshoot had only started within the last two to three years, while the tree would be around the same age of the house.

It is a well-established engineering fact that impermeable method of paving where used, will prevent water from penetrating into the ground and can affect the shrink-swell behaviour of the ground. A well-designed permeable paving system, in good condition may actually reduce the amount of shrink-swell activity in the ground immediately below it.

The Institution of Civil Engineers, write that paving moderates variations in water content of the soil and thus the range of shrink-swell behaviour that might be expected.

In our opinion, the thermal balance of the ground beneath and around the offshoot, over time, can increase the likelihood of soil settlement or reduce soil stability and particularly in clay soils, which would affect shallow foundations and hence the structural stability of the building.

We noted that a plastic grass (Synthetic Turf) has been laid over a compacted sub base, up to and abutting the offshoot flank wall. Those alleging tree root shrinkage, cannot say when this synthetic turf was laid, or how it correlates with this change in the offshoot paving and the reported subsidence.

We have searched research studies regards ‘Temperature Amelioration of Synthetic Turf Surfaces’ and we have found that the surface temperatures of synthetic turf (plastic grass) are significantly higher than natural turfgrass surfaces when exposed to sunlight. Reports indicate the surface temperatures of traditional synthetic turf can as much as 35-60°C higher than natural turfgrass surface temperatures. Penn State University’s Centre for Sports Surface Research conducted studies comparing surface temperatures of synthetic turfs composed of various fibre and infill colours/materials and found that the maximum surface temperatures during hot, sunny conditions averaged from 140° F to 170° F. Another study conducted at Brigham Young University found that “The surface temperature of the synthetic turf was 37° F higher than asphalt and 86.5° F hotter than natural turf.”

In our opinion (and without sampling or testing) significant heat increase, beneath the synthetic turf and it’s impermeability would have a significant effect on moisture content in the Active Zone, we estimate in the top 600mm of sub soils.

We have not accepted culpability for the movement affecting these shallow foundations and we have recommend to those allegedly tree root shrinkage, that before we consider felling the tree, which has an environmental, social and neighbourhood benefit, that the Synthetic Turf be lifted and replaced with a permeable paving.

Alan Holmes DipSurv, MRICS, CBuidE CABE, MCIAT

Institution of Civil Engineers, Manuals series. CHAPTER C5 – EXPANSIVE SOILS
Lee D Jones, British Geological Survey. Ian Jefferson, School of Civil Engineering, University of Birmingham

Experimental Research of the Heat Transfer into the Ground at Relatively High and Low Water Table Levels
Tadas Zdankus * , Juozas Vaiciunas and Sandeep Bandarwadkar

Temperature Amelioration of Synthetic Turf Surfaces through Irrigation
A.S. McNitt, D.M. Petrunak, and T.J. Serensits

25/08/2023

Alan Holmes Building Surveying Services (AHBSS) proud sponsors of Whitley Bay beer festival. AHBSS your local surveying practice.

28/07/2023

We have been surveying other matters on a 20 years old building in Northumberland and we identified vertical cracking close to an eaves corbel detail, which caused us some concern. A further inspection revealed cracking affecting eighth of twelve corbel details.

The corbel details are between four course and six course of projecting bricks. The bricks corbel 55mm (¼ brick) in each course, projecting therefore between 220mm and 330mm.

NHBC Guidelines section 6.1 ‘External Masonry Walls’ states:
‘’For feature brickwork sections the masonry should only be self supporting. Where courses are corbelled outwards in ordinary masonry, one above another; the extent of corbelling should not exceed that shown in the diagrams on the right. Where reinforcing is used, corbels should be designed by an engineer in accordance with Technical Requirement R5’’.

To comply with NHBC Guidelines the maximum corbel, overall from the face of the wall, is T/3.Which is one third of 300mm = 100mm.

Each corbel exceeds NHBC Guidelines.
The corbel is outside of the NHBC Guidelines and should have been a Structural Engineered designed detail. The direction and mode of cracking indicates that this corbel has already started to rotate. The rotation will only get worse with a risk from falling masonry if left unchecked.

07/07/2023

There are lots of changes coming to the Building Safety Act and a number of important timelines.

Transitional Requirements for High-Risk Buildings
Up until 1st October, a client, wishing to make alterations or improvements to a high-risk building, can appoint a Building Control Body from either the Local Authority or an Approved Inspector in advance of the works. There is a specific legal definition of "high-risk building" and "building". A High Risk Building is defined as:
o 18m or 7 Storey in height
o With at least two residential units
o Care Home
o Hospital
Submission to Building Safety Regulator (BSR)
From 1st October, if no previous application has been made to an LABC/Approved Inspector, any works for the er****on or alteration of a high-risk building must be submitted to the BSR. Obtaining certification from the BSR involves a fundamentally different process compared to the Local Authority/Approved Inspector process, and applicants will be subject to the new "Gateway" procedures.
Transition Period for "In Flight" Applications
Applications submitted to an Approved Inspector/Local Authority before 1st October 2023 are considered "in flight" applications. Transition period:
• The Approved Inspector must have been granted a "Registered Building Control Approver" (RBCA) license by the BSR before 1st April 2024.
• If works are commenced prior to 1st April 2024, the RBCA/Local Authority can continue to be the Building Control Body on the project.
• From 23 January 2023, the following fire safety regulations came into force:
o The Fire Safety (England) Regulations 2022 introduced new duties for building owners or managers (Responsible Persons) under the Regulatory Reform (Fire Safety) Order 2005.
• From 6 April 2023, the following building safety regulations came into force:
o The Higher-Risk Buildings (Descriptions and Supplementary Provisions) Regulations 2023: Determine the buildings subject to the new safety regime established by the Building Safety Act 2022 in England.
o The Higher-Risk Buildings (Key Building Information etc.) (England) Regulations 2023 No.396: Set out the requirements for "key building information" in higher-risk buildings, duties for submitting such information, and determining the responsibilities of the Accountable Person (AP) under the Building Safety Act 2022.
o The Building Safety (Registration of Higher-Risk Buildings and Review of Decisions) (England) Regulations 2023: Require all higher-risk buildings to be registered with the Building Safety Regulator by 1st October 2023. The registration application must include details about contact information for each AP, a building description, and information regarding building control approvals. A £251 registration fee is payable at the time of application. In case of any changes to the registration information, the Principal Accountable Person (PAP) must notify the Building Safety Regulator within 14 days of becoming aware of the change.
The Home Office has also published guides to fire safety for smaller premises and a Fire Risk Assessment Prioritisation Tool.
Registration Process for High-Rise Residential Buildings
On the 12th of April 2023, the Building Safety Regulator opened the registration process for high-rise residential buildings in England. It is a legal requirement under the Building Safety Act 2022 for all high-rise residential buildings:
• 18 meters tall or higher, or at least 7 storeys tall,
• With two or more residential units,
To be registered with the Building Safety Regulator by the 1st of October 2023.
The Principal Accountable Person (PAP) for each building, or someone authorized by them, is required to complete the registration process and the fee to register each building is £251.

05/06/2023

One of the most common problems we come across when surveying 1850 to 1939 houses is stepped cracking and sagging brickwork and lintels over single storey bay windows. When a beam of whatever material is loaded an initial deflection occurs and with steel or concrete that is the end of the matter. However, timber under prolonged high stress will very gradually continue to deflect with the passing of years, a phenomenon known as creep deflection. This is probably the most common cause of failure with timber lintels. The structural member most at risk is the beam, or bressummer, supporting the external wall and first-floor over a single-storey bay window and often the whole street of similar houses will exhibit the same pattern of stepped cracking above the bay window.

The beam or bressummer is normally made up of three of four floor joists with spacers between to make up the wall thickness, whilst the floor joists either go over the top and form the ceiling/roof to the bay or more commonly are tusk tenoned into the inside joist.

If the cracks are just caused by nothing more sinister than creep deflection and provided the bressummer is adequate in other respects, then normally all that is needed is to rake out the cracked joints and repoint.

However, if the property is earlier than about 1920 and the bay has a flat roof it would almost certainly have been leaded. Sheet lead has a life of about 50 years after which deterioration occurs either by splitting dues to thermal stress or the formation of pin holes caused by corrosion or breakdown of small foreign particles in the original lead. This leads to water pe*******on which if neglected could lead to wet or dry rot in the bay roof timbers or the bressummer. If the lead has been replaced with felt is usually a sign that there has been water pe*******on in the past and it should be treated with suspicion.

The properties most at risk are houses built prior to 1920, with a flat roof over the bay that has had the original lead replaced. If in these circumstances the cracks are relatively recent and show on the inside as well as the outside of the wall it can be assumed that there is probably wet or more likely dry rot in the bressummer, in which case it must be removed and replaced with a steel beam. Unfortunately, it is not easy to check whether the bressummer has been affected by rot without extensive opening up.

Today I have had the opportunity to carry out this further inspection and examine exposed beams over a front bay opening and rear wall bay opening.

In this 1900 to 1910 semi-detached two storey house, with front single-storey bay and lean-to tiled roof and a dining room (rear wall) bay, there was significant falls in the stone cills of the main bedroom front wall directly over the single-storey bay opening and a diagonal crack in the inner leaf brickwork. In the rear bedroom, rear wall there was a stepped crack directly above the opening into a dining room bay opening.

We ordered the bressummer to be opened up expecting to find rot in the timber beams. We were pleasantly surprised to find, that there two heavy 75mm 290mm timber beams with metal ties and supporting the first-floor joists, on top of the lintels and not tusk tenoned into the inside joist.

We inspected the beams, particularly their end bearing, and we found no evidence of fungal decay or insect attack. The timbers other than having undergone defection over their 100 years life remain structurally sound and by inspection are adequate to support the loads imposed.

In addition, we noted that there is a brick arch above the front bay and this will accommodate much of the inner leaf loading.

The bay ceilings and downstand can be re-instated and there is no need, in our opinion, to replace the Bressummer, which will happily continue to deflect for another 100 years.

23/05/2023

Keeping on the theme of clay tiles, I surveyed a roof with Beauvais tiles recently. Tuileries De Beauvais or Beauvais Diamonds are decorative double interlocking clay roof tiles of French origin. The rare roof tiles are often terracotta red in colour but can range from pale red to dark brown and even black in some cases. The tiles are made from terracotta clay, terracotta is not only a term that refers to colour, it also means a ‘sculpture made of earthenware’, which gives an indication as to how these roof tiles were originally fabricated. It is likely that original tiles of this design were moulded by a craftsman by hand, before being cooked on a wood fire where the clay could solidify, forming the roof tile. Today, traditional clay roof tiles such as these have been replaced by mechanical tiles that are moulded, compressed and baked.
There are many French clay roof tile designs available, the Beauvais diamond double interlocking tile however is seemingly rare nowadays, consequently seeing a roof decorated with this specific roof tile during a building survey was quite unique. Due to the rarity of these specific clay roof tiles maintenance is likely to be expensive, obtaining Tuileries De Beauvais in a decent condition for maintenance roof repairs may be a difficult task without paying a high price. In terms of when maintenance repairs are to be expected; clay roof tiles often have a relatively long-life expectancy but to give an exact date is near impossible. The factors that affect the life expectancy of this type of tile are as follows, the quality of the original manufacture (of which Beauvais diamonds are regarded as high quality), the firing in the kiln and the make-up of the material within the tile itself.
Apart from the awful repairs and terrible repointing of the hip tiles, these tiles had remained in very good condition after 100 years and are a testament to their quality manufacture. There is however no secondary membrane and the original lime mortar with horse hair torching has all but fallen away leaving the roof susceptible to wind driven rain and subsequent rot in the battens.

23/05/2023

Clay roof tiles have been used since the 13th century and have proven their durability. In the mid 1920's clay tiles in the UK were more difficult to source and the Courtrai clay tiles were imported from Europe and became regular features on British rooftops during the early 1900’s. However, these clay tiles lost popularity with the manufacture of cheaper concrete tiles in the 1960’s.

There are still many roofs with clay tiles that have survived hundreds of years, but many don’t make the grade. Unlike slate, clay tile life expectancy depends on how they were manufactured, and these Courtrai tiles were a mass produced product imported all over the world. Their colour was said to be permanent, but it was found to fade with time. Indeed, the elements work with the clay to produce a weathered and mellow appearance, improving their looks with age.
The roof is arguably the single most exposed face of any structure! It has to withstand rain, wind, ice, ultra-violet light and, increasingly, the effects of damaging acids caused by atmospheric pollution. Clay tiles are fire resistant, able to withstand harsh chemicals and are not susceptible to biological degradation, they do not harbour excessive mould growth and are not affected by extremes of heat or cold.
The life span of a clay tile is influenced by the type of clay, the way it is manufactured, the dampness of the atmosphere, the position of the building and the pitch of the roof. All these factors will influence the speed of the weathering process.

Clay tiles do not fair well in freezing temperatures. As rain, then freezing temperatures can cause delaminating of the clay surface. The photographs attached show early stage cracking and splitting (spalling) of the clay tile and on the start of delamination of the tile surface.

The tiles are hooked over the tiler’s laths and these are nailed (some roofs are not nailed others nailed every fourth course). The underside of the clay tiles are often affected by condensation and subsequent spalling. This particularly affects the nibs and when these spall the tiles slip. The photographs below show many nibs spalled away and another cracked but still in place around a rusting nail. The rust expansion of the nail causing the nib to crack and fall away.

The laths are set at predetermined gaps (Gauge), which dictates the lap of the tiles. The laths can suffer from rot particularly when the torching is missing and the rot can cause the loss of fixing between battens and rafters.

From around 1960’s (following introduction of the Building Regulations) roof slates and tiles have been laid over a secondary water protection system called ‘sarking felt’. Before the introduction of the sarking felt, the tiles were pointed with lime mortar (sometimes mixed with horse hair) between the laths and underside of tile, commonly called ‘torching’. The torching prevent wind driven rain pe*******on. However, in this instance all of the torching had fallen away an indication that weathertightness may have failed. This leads to increase water ingress from window driven rain and this then causes the nails to rust, the loss of the nibs and increased risk of tile slippage.

16/12/2022

With prolonged cold snap we invariably get concerned clients complaining that their boiler has stopped working, and today they have both said ‘and it’s only two years old’. I have explained that commonly it is the condensate that has frozen, and the boiler safety mechanism shuts the boiler down. My client defrosted his pipe and with some gentle persuasion got this much ice form his 4m long condensate pipe.
Where a condensate pipe from the boiler runs through an unheated space (garage, loft space or sub floor void for instance) or externally along or down a wall, it has the potential to freeze. It takes a while, the condensate does not flow, it trickles, and this gives it time to freeze, then the next trickle freezes, and so on until it blocks the pipe.
In April 2005 revisions to the Building Regulations came into force, stating that all replacement gas or oil boilers must be a condensing type. The introduction of condensing boilers has been fundamental in reducing the UK’s carbon emissions. Typically, a 24kW boiler will produce around 1.7 litres of condensate per hour. In 2010 and again in 2018 the UK experienced prolonged spells of sub-zero temperatures down to minus 20 centigrade and below in many areas. This resulted in a significant increase in the number of calls to boiler manufacturers and heating engineers from householders with condensing (high efficiency) boilers where the condensate discharge pipe had frozen and become blocked with ice causing the boiler to shut down. In the vast majority of cases such problems occur where the condensate discharge pipe is located externally to the building for some part or all of its length.
To minimise the risk of freezing in the condensate pipe during prolonged sub-zero conditions, an internal “gravity discharge point” such as an internal soil stack (preferred method), where possible.
Internal condensate discharge pipework must be a minimum of 19mm ID (typically 22mm OD) plastic pipe or as per manufacturer’s instructions and this should “fall” a minimum of 45mm per metre away from the boiler, taking the shortest practicable route to the termination point. (45mm as per BS6798, 52mm per metre as per industry practice is specified in the following diagrams). The possibility of waste pipes freezing downstream of the connection point should be considered when determining a suitable connection point - e.g. a slightly longer pipe run to an internal soil stack may be preferable to a shorter run connecting into a kitchen waste pipe discharging directly through the wall to an external drain. However, where “gravity discharge” to an internal termination is not physically possible (e.g. the discharge point is above the appliance location, or access is obstructed by a doorway), or where very long internal pipe runs would be required to reach a suitable discharge point, then a condensate pump should be used. External pipe run should be kept as short as possible to a maximum of 3 metres, taking the most direct and “most vertical” route to the discharge point, with no horizontal sections in which condensate might collect.
The external condensate pipe should be covered with thermal insulation to retain heat losses from the pipe. All other relevant guidance on condensate discharge pipe installation should also be followed. Insulation Materials Insulation used for external condensate pipes, should be of class ‘O’ grade with an outer coating that is weather proof, bird/animal proof, and UV resistant finish. A minimum of 19mm thick insulation is recommended for 32mm external pipes.
When a condensate pipe terminates to an external soil stack or rainwater downpipe (NB only permissible if this downpipe passes to a combined foul and rainwater drainage system) an external air break must be installed between the condensate discharge pipe and the downpipe to avoid reverse flow of rainwater/sewage into the boiler should the downpipe itself become flooded or frozen.
Where an internal condensate drainage pipes runs through unheated areas such as lofts, basements and garages, the pipe should be treated as external connections and insulated accordingly.
If you have a lengthy external condensate pipe, or one that runs through an unheated space, a Gas Safe engineer should inspect and review the boiler condensate pipe arrangement.

15/11/2022

I have been asked to put together a specification for door replacement on a four storey 1960’s block of apartments. The doors (fitted with self closures) form part of a screen onto a protected means of escape route and they are twisted slightly and do not have smoke seal or intumescent strips.
The Regulatory Reform (Fire Safety) Order 2005 [(RR(FS)O] applies to communal areas and means of escape route.
The means of escape route has a Grade A LD2 fire alarm and detection system to provide an early warning to the residents in the event of a fire and emergency lighting.
The apartments have an escape route that can resist fire, smoke and fumes long enough for everyone to leave (usually at least 30 minutes). This being an internal staircase in non-combustible material and ground floor corridor that are specially constructed or treated to resist fire. All the walls, ceilings, floors and partitions along the escape route are fire resistant. But the screen on each landing between mean of escape staircase and the apartments is Georgian wired glass and timber frame.
The local Fire & Rescue Service are now involved and they may serve a legal notice and could even prosecute if the doors are not improved.

I have asked for the building RR(FS)O audit and risk assessment and if a competent person (or consultancy) has approved the fire rating of the screens (Georgian wired glass and wooden frame) because Georgian Wired Polished Plated (GWPP) certified to be fire rated as part of a proven system. The glazing system (GWPP) is only truly fire rated if all elements are considered, as one. It is imperative that the glass be certified that the glazed doors and the support and framework and structural screens were certified to provide relevant fire safety and still compliant. Any design I need to do, must offer integrity-only protection against the passage of flames and toxic gases for 30 to 60 minutes, fire tested to BS476: Part 22: 1987.

15/11/2022

An important case for those with high-rise buildings and cladding issues. Martlet Homes Limited -v- Mulalley and Co Limited [2022] in the Technology and Construction Court (TCC). The first case for High Court judgment on a claim concerning fire safety defects in cladding on a high-rise building following the Grenfell Tower disaster in 2017. On Thursday 14 July 2022, HHJ Stephen Davies held in favour of Martlet Homes Limited (Martlet) a Housing Association.

Martlet’s claim against Mulalley and Co Limited (Mulalley) concerned defective design and installation of cladding supplied by Sto Ltd, which was installed by Mulalley at four storey rise residential towers in Portsmouth.

Mulalley (Contactor) argued that Martlet’s had undertaken works remove and replace the cladding at the Gosport Towers on the basis of post-Grenfell concern over the presence of combustible insulation within the system, rather than as a result of the defects in Mulalley’s installation.

HHJ Stephen Davies found that the workmanship defects for which Mulalley were responsible were an effective cause of Martlet’s loss and awarded Martlet substantial damages for the remedial works it undertook to address the defects in the cladding system and also awarded Martlet damages for the substantial costs of the ‘waking watch’ service implemented by Martlet as a temporary mitigation measure for the risks posed by the cladding pending it’s removal.

This is a significant outcome, not only for the Claimant, but for many UK building owners facing similar cladding issues. Because, the Judge found that Mulalley’s use of the Sto cladding system, which incorporated combustible EPS insulation panels, was both a breach of contract and a breach of the Buildings Regulations in force at the time of installation.

Specifically, Mulalley was found to be in breach of its contractual obligation to ensure the cladding system followed the recommendations and advice in BRE 135 (2003). Although the Judge noted that BRE 135 “could have been clearer” in its identification of the relevant design principles and performance standard for external wall systems, he found that “any careful reading of the document, especially by any construction professional with fire safety related knowledge” would have revealed that the performance standard in Annex A of BRE 135 should have been considered and complied with by a cladding specifier in the case of a high rise building with sleeping areas.

Mulalley attempted to rely on the BBA Certificate for the Sto Therm Classic K cladding system installed at the Gosport Towers in defence of Martlet’s alternative case, but the Judge held that contractors and designers cannot point to a BBA Certificate as a “guarantee” or “passport” to compliance with the Building Regulations. The Judge ultimately found that the system failed to meet the functional requirements of B4 (1) of the Building Regulations.

AHBSS

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