Cracks are the most common type of problem in any type of building. However, most people don’t know whether they should be concerned. Due to faulty steps during construction or unavoidable reasons different types of cracks form in parts of the building over a length of time. In this blog post, we will look at some of the types of cracks that can occur, what they mean and what type of repair is necessary.

Active or Dormant?

Cracks can be defined into two main categories – Active or Dormant.

If cracks are active, they show some movement in width, depth or direction over a measured period of time. These are different from dormant cracks, which remain unchanged over a measured period of time. Active cracks tend to be more serious than dormant cracks, as some active cracks can be structurally hazardous. This makes timely identification and the adoption of preventative measures essential to the integrity of the building. However, if dormant cracks are left unrepaired they can lead to a variety of different problems such as moisture penetration.

So, what causes cracking?

So we know that cracks are active or dormant, but why did they form in the first place? Below, we will look at the most common causes of cracking in buildings.

1. Subsidence

Subsidence is simply the downward movement of the soil beneath a building. By far the most common cause of subsidence is the action of tree roots on shrinkable clay-rich soils. If a tree is allowed to grow in close proximity to a house which sits on clay, the tree will draw up considerable amounts of water which will cause the clay to shrink and the house to subside. Another common cause of subsidence are broken drains which cause water to leak out into the clay which over time weakens it significantly.

Subsidence cracks are most commonly wider at the top of a property. The cracks will generally travel diagonally in opposition to the downward movement.

To repair subsidence the tree must be removed in stages (to avoid heave – below) and the property underpinned. Significant cracks can then be repaired and repointed.

2. Heave

Heave is the opposite of subsidence, meaning that it is the upward movement of soil. This is caused as a result of dry soils expanding due to water being reintroduced. The most common situation when heave occurs is when a large tree is removed and the water which it would have drawn up is now introduced back into the soil. This is why trees should be removed in stages over a period of time to avoid sudden heave.

Where heave occurs cracking is normally wider at the bottom of the property. The cracks taper as it rises and cracks generally occur at right angles to the diagonal and upward movement.

3. Settlement

Settlement is the downward movement of a property which has been newly constructed. This can also occur if you extend your property and cause additional load to be applied to the soils. This is a process of soil consolidation and tends to occur once over a period of time and then cease. This must be carefully controlled in the design of a new property, but generally should only be considered worrying if there is a major error in construction or design.

If cracking has been accommodated then decorative repairs only will normally be necessary. If the cracks are very significant then some more intense repairs may be involved (repointing, wall-ties, etc.)

4. Thermal Movement

5. Seasonal Movement

In the UK, we are particularly subject to the four seasons which will affect shrinkable soils (clay and silts) in different ways. In the summer clay will shrink as it dries out, and some soils will expand during the winter months with heavy rainfall. Older properties will have relatively shallow foundations and will be more subject to seasonal movement than newer properties. Seasonal movement causes cracks which open and close throughout the varying seasons. These cracks are generally insignificant and can be dealt with through standard decoration.

Damp refers to the presence of moisture, water, and condensation being present within a property. Dampness occurs quite frequently in different properties but tends to be commonplace in those that are older or have not been properly maintained.

Rising Damp

Rising damp is perhaps the scariest type of damp for all prospective homeowners or first-time buyers. Rising damp particularly occurs in older properties, where a lack of effective DPC (Damp-Proof Course) allows water to rise up through floors, walls, and masonry. Bricks and mortar can be porous, allowing the water to travel up the minuscule holes and into your property.

These are the common symptoms of rising damp in your property:

• Tide marks on the wall, up to one metre high, which leave a visible residue of water and salts
• Smells or a musty odour
• A reduced temperature at the lower portion of the wall
• Rotting of embedded floor timbers
• Crumbling or blistered plaster due salt crystallisation

Walls are then often contaminated with salts that mean it is not possible to just re-plaster and hope the problem will go away. The best method is to remove the plaster on offending walls to about 1.2m in height, dry and re-plaster. Liquid DPC’s can then also be injected.

Penetrating Damp

Penetrating damp is the most common form of water-ingress in your property – but is particularly prominent in buildings with solid wall construction or cavity walls where the insulation has been fitted incorrectly or in unsuitable walls. It is caused by water permeating through walls from the outside.

These are the common symptoms of water penetration in your property:

• Localised Dampness – Dark patches on external walls
• Plaster Damage – Plaster & paint deterioration, blistering, the appearance of stains & salts
• Wet Rot — Rotting skirting boards or timber
• Moss — Excessive moss growth on external walls.
• Brick Deterioration — Moisture entering the brick (spalling) causes surface damage
• Mould — Mouldy scent or signs of mould growth on internal surfaces

The most common way to tackle penetrating damp is by painting exterior walls with a clear waterproof masonry coating.

Condensation

Excessive condensation simply caused by too much water vapour inside the house, usually due to poor ventilation or as a result of another form of dampness. Condensation occurs in properties of all ages and occurs when this warm water vapour hits a cold surface, like a window.

• Steaming windows
• Patches on walls, particularly occurring behind furniture and in corners.
• Peeling wallpaper
• Black spots on window and door frames
• Mould growth (usually black mould)
• Soft furnishings and fabrics prone to mould and mildew

Black mould is a potentially life-threatening issue for a young child, the elderly or anybody with a pre-existing lung condition. The most common way to remedy condensation dampness is by installing more effective methods of ventilation.

Proper maintenance on the gutters at your property is perhaps the most important thing you can do to prevent water penetration and damage to your home. Gutters are actually designed to do one thing — channel water away from the foundation — and they’re critical to protecting the structural integrity of your house. A whole host of reasons can lead to faulty gutters – Ignorance and money saving can result in lack of maintenance or inappropriate replacements.

Here are the 3 Most Common Types of Guttering in UK Homes:

uPVC Gutters

 PVC is the most common type of gutter found on newer buildings and the most typical replacement for the older cast-iron gutters. They are inexpensive, light and easy to fit, with no painting required. uPVC gutters tend to come in white or black and are made of unplasticised polyvinyl chloride – A rigid, chemical-resistant plastic.

Aluminium Gutters

Aluminium gutters are lighter than cast-iron gutters. These are rust-resistant because as the metal corrodes it creates a hard finish to the surface, adding further protection. They come in many shapes are desirable as they can replicate traditional styles of cast iron gutters, without the rust or the weight. Aluminium gutters are not commonplace as uPVC is a cheaper alternative.

Cast Iron Gutters

If you live in a period property,  it is likely that your gutters and downpipes are made of cast-iron and painted for additional protection. These are quite heavy compared with uPVC or aluminium gutters.

Common Guttering Problems:

Clogged Guttering

When a gutter becomes blocked the water will overflow onto your external wall. A common cause of overflowing gutters is fallen leaves, moss growth, vegetation growth, and birds nests blocking the gutters; preventing rainwater from traveling to the downpipes and out into the drainage system.

Gutters must be unblocked before the organic debris completely blocks your gutters, scooped out from gutters and pushed out of downpipes using drainage rods. There are preventative measures you can take such as wire mesh or plastic balloons in the outlet, allowing clearance to take place before downpipes become blocked. This cleaning tends to happen after the leaves have fallen in the autumn. Every few months hoppers (box on top of downpipes) should be checked and cleared.

Sagging Guttering and Guttering Coming Away from the House

This tends to be caused by a fault with the hangers – the brackets that secure the gutters to the fascia. They might have deteriorated over time, the screws/nails may extracted from the wood due to rot, or they’re spaced inadequately to support the weight of full gutters. The cost to fix this issue is inexpensive and easy to carry out.

Holes and Leaks

Joints between different sections of guttering can leak, but can easily be fixed by using sealant on the inside. Small holes can be filled with gutter sealant but larger holes will require a patch, using another small section of guttering or metal flashing.

Missing Guttering

Gutters are only useful if they are present, so an adequate system must be fitted to provide a channel for water to be moved away from the foundations of a building.

Improperly Pitched Guttering

Gutters need to be pitched toward the downspouts for the water to flow properly. You want a fall of 1cm for every 3.5 metres of guttering.

1. Damp to External Walls

Commonly caused by the failure of the Damp Proof Course (DPC) or bridging the DPC by increasing external ground levels (usually 150mm above ground level)

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2. Failed Gutters & Downpipes

The most common failure points of rainwater goods are at the corners of guttering, joins and rainwater outlets. A blocked gutter can cause damp issues / failure of masonry and can lead to structural issues if left long enough. The most common guttering defects are blocked rainwater outlets, corroded gutters, cracked guttering and failure of rainwater goods below ground level.

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3. Roof – Structural Failure

In regards to roof structure, a whole host of defects can occur. These include woodworm, wet & dry rot, roof spread and sagging of purlins (a horizontal beam along the length of a roof, resting on principal beams and supporting the common rafters or boards).

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4. Roof – Coverings Failure

One of the most common failures of slate roof coverings are the nails holding the tiles to the batons corroding and causing the slates to move and slip out of place. Where concrete or clay tiles are used the tiles can crack and spool, leading to water ingress and structural problems due to rotting roof structures.

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5. Structural Alterations

A lot of residential defects are caused by alterations to the original structure, where proper materials or expert design haven’t been used. For example, if a load bearing wall is removed, a proper steel structure design must be used to ensure the load can be taken safely and without fault.

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6. Condensation

Condensation dampness usually occurs when there is a high ‘relative humidity’ level, a measure of  moisture content within the air.  As the relative humidity increases past 100% moisture droplets form as condensation on cold surfaces. Many factors could cause the relative humidity to rise including a lack of proper ventilation, the number of building occupants, drying clothes internally or cooking.

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7. Condensation in Windows and Doors

The most common issue with uPVC doors and windows is condensation within the sealed double glazed unit, due to the degradation of the seals.

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8. Defective Flat Roof

Older flat roof’s are generally constructed with a mineral felt or asphalt covering. These types of coverings generally have a life span of 10-20 years and therefore commonly found to be defective. Newer coverings, such as GRP (Glass Reinforced Plastic) can have a life span of 40 years + if maintained correctly. UV rays can cause degradation to the outer surfaces and there can be weathering and cracking to the various layers. Other defects can include faulted flashings and ponding – meaning that the roof does not drain effectively.

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9. Structural Movement

Cracking, bowing or leaning walls and sticking doors or windows are all indicators of structural movement in your house. The main types of structural movement are subsidence, heave, settlement, thermal movement and seasonal movement.

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10. Eroded Pointing

Pointing to masonry walls used to be a lime based mix on older properties, however, on newer properties a harder cement based based mix is used. Pointing generally occurs to brickwork exposed to the elements and weathered over time, or due to failed guttering.