What is carbonation of concrete?

Carbonisation is the reaction of carbon dioxide in the atmosphere with calcium hydroxide in the cement. This reaction produces calcium carbonate, which in turn impairs the protection offered by the concrete to the embedded steel reinforcement. Where the steel is too close to the concrete surface, carbonisation will cause the embedded steel to corrode and expand, causing the concrete to fracture and spall. Our structural engineers can investigate whether carbonisation is affecting the strength and durability of your building and provide specifications for appropriate repairs.

What is Japanese knotweed?

The Environment Agency describe Japanese knotweed as the UK’s most aggressive, destructive and invasive plant. It can grow to 3-4m in just 10 weeks. Below ground, its roots can spread 7m horizontally, and can compromise the structure of a building. In a house sale transaction, its presence can be a deal breaker. Lenders can be very nervous about mortgaging a property that has Japanese knotweed on the site. Correct treatment and eradication must be completed by specialist contractors, who must dispose of it off site to a licensed tip. We can advise you if your property has Japanese knotweed, and we can use our network of specialists to help you.

Why is the brickwork above my windows cracked?

Cracking to the outer leaf brickwork above window and door openings is not unusual. Sometimes the cracking occurs simply as a consequence of thermal movement of the wall materials. In other instances, the lintel which is intended to support the wall over the opening, is either inadequate or has been omitted altogether. Our survey will establish the cause of such cracking and recommend appropriate repair work.

Can I change the use of my building?

If you intend to change the use of a building, then there may be structural implications. Other than planning restrictions, the building needs to be fit for purpose and be capable of supporting the loads imposed by the new use. Our engineers can survey the property and assess the current load carrying capacity of the building and establish if the structure is capable of supporting the new loads imposed upon it. If not, we will advise on any associated strengthening works considered to be necessary.

Can I alter a Listed building?

Any work that you plan to do on a listed building, including extending, demolition and anything that may affect the character as a building of special interest, will require Listed Building Consent, irrespective of whether normal planning permission is required or not. This will include any structural repair work that is required to restore the stability and strength of the building. The consent is either determined by the local planning authority or in some circumstances, the Secretary of State. Failure to obtain such consent is a criminal offence. We can provide the technical support that you require to obtain consent, and negotiate with the local authority heritage representatives, on your behalf.

What is a system built house?

Traditionally, houses are built with brick, stone and concrete block work walls, supporting timber suspended floors and a timber roof structure. Mortgage companies tend to prefer traditional forms of construction, as they are well documented and their performance is understood. System built houses were introduced after World War II, to speed construction and produce houses in large numbers. These systems included steel framed houses and pre-cast concrete panel houses. Most were associated with social housing. Often, Lenders are reluctant to provide mortgages on such houses, unless a structural engineer inspects the property and provides the required reassurance of future integrity.

What is sulphate attack on floors?

Concrete floor slabs sit on a hardcore sub-base. In the past, some hardcore has contained industrial waste products including sulphates. When moisture is present, these sulphates can migrate into the body of the concrete slab, causing an expansive reaction. Common signs of this are uneven floors that have lifted in places, and randomly cracked. This problem can be serious, especially if internal walls have been built off the affected floor slab. Repair works can be disruptive and costly. Our structural engineers can investigate whether a floor has been affected by sulphate attack, carry out intrusive testing and then provide a specification for these works.

Has my house been affected by bomb damage?

In the north of England, many of our industrial towns and cities were targeted during World War II, in an attempt to destroy our manufacturing capability. As a consequence, residential areas were also affected by the bombing and houses were damaged. The resulting distortions are still evident today but are not necessarily of structural concern. Our engineers can review bomb data and advise you on the likely impact of such damage.

How does hot weather cause foundation movement?

Periods of prolonged dry weather often lead to increased incidents of subsidence claims with insurance companies. Older properties tend to have much shallower foundations than modern properties. Those that are built on clay soils are susceptible to the effects of clay shrinkage, brought about by prolonged dry weather. The foundations can fluctuate in level on a seasonal basis, dropping in summer and lifting in winter as the moisture content of the clay varies. Our engineers can arrange examination of the foundations and laboratory testing of the soils, to establish susceptibility to movement.

Can trees cause foundation movement?

Yes. In clay soils, trees can be a significant problem to a property, especially if growing in close proximity. Trees will extract water from the clay, which in turn will cause the clay to shrink. Any foundation built on this clay would then move downward. Sudden removal of trees can have the opposite effect, causing the clay to rehydrate and expand, which in turn may result in the foundation lifting. In granular soils, the physical presence of tree roots can also disturb the foundations. Our engineers can carry out a detailed analysis of the effect of trees and vegetation on the stability of your property.

Can drain defects cause foundation movement?

Yes. If drains running close to a foundation are defective and water is escaping from the drain, then the strength of the ground supporting the foundation can be impaired. In these situations, we can arrange CCTV surveys of the drainage system to identify the location of any damage, and advise on appropriate repairs, to prevent future movement.

What is roof spread?

A house roof is usually an internal timber structure, clad with tiles. The structure is supported off the external walls. In certain circumstances, the timber structure will shift outwards at the top of these walls, albeit slowly. This, in turn will cause sagging of the roof slopes and the ridge of the roof. Causes of such distortion include inadequacy of the supporting timber roof structure and replacement of the original tiles with heavier, concrete tiles. Our engineers can inspect the internal roof structure and assess its suitability to support the weight of the tiles and solar panels, if fitted.

What causes distortion to walls?

Wall distortions are sometimes observed to external walls of a property. A wall will occasionally appear to bulge outward. There are many causes of such distortion, including wall tie failure, foundation movement, inadequate tying of the wall back to the internal floors and walls and poor workmanship. Our experience will pin point the cause and provide you with recommendations on appropriate repair works to ensure future stability.

What is meant by monitoring of cracks?

It is important to know if movement to a property has ceased, or is still active. Monitoring will provide you with that reassurance, or indeed confirm that stabilising works will be required to arrest the movement. A monitoring programme will be managed by a structural engineer, and will usually involve accurate measurement of crack widths at various locations around the property over a period of time. This often will be over a 12 month period, to assess movement throughout each season in the year.

What is underpinning?

Occasionally, investigations will conclude that part or all of the foundation is inadequate to support the weight of the building. This might be due to the foundation depth, width or the poor strength of the sub-soils. Underpinning extends the depth of the affected foundation down to a suitable level, to ensure future stability. Traditionally, this can be achieved by excavating below the foundation and placing new concrete below. Occasionally, the underpinning may need to go deeper, and a mini-pile solution may be adopted.

What is a Damp and Timber Survey?

A Damp is commonly found in properties of all ages, styles and stature. Damp can be identified visually by staining and disruption to plaster finishes, salt deposits and mould growth. There are many forms of damp and associated causes, including rising damp, penetrative damp, salt contamination, plumbing leaks and condensation related damp, all of which can be attributable to one or more of the aforementioned visual identifications. Where prolonged damp is found, there becomes an increased risk to any timbers in contact with the damp substrate. Ultimately this often leads wood destroying fungal attack of the timber, otherwise known as rot or timber decay. This timber can be non-structural such as skirting boards or door frames etc. but can also be structural timbers such as floor joists, elements of the roof structure or lintels amongst many others. Another risk to timber is wood destroying beetle attack, commonly known as Woodworm. Extensive infestations can lead to significant loss in strength of the timber elements and can be identified by flight holes left in the surface as the beetles emerge from the timber. There are a number of types of wood destroying beetle most of which can be identified by the characteristic damage they leave behind. A specialist damp and timber survey would typically involve an inspection of the property to visually identify any areas of damp or water related damage. The inspection would also include a check of surface finishes with a damp meter to identify any elevated levels of moisture content within the construction materials. If specifically requested or instructed, the inspection may include lifting of floor boards to inspect sub floor areas for signs of damp related damage or wood destroying beetle attack. As part of the report the cause of the damp will be assessed and recommendations given for repairs and treatment works, whether these be damp proofing, wall finish treatments or improvements to ventilation etc. It should be ensured that the survey is completed by a Property Care Association (PCA) approved contractor or surveyor.

How does radon affect my property?

Radon is a colourless, odourless radioactive gas formed by the radioactive decay of small amounts of uranium that occur naturally in all rocks and soils. Every building contains radon, but the levels are usually very low. The chances of a higher level depend on the type of the ground and locality. Our structural engineers can review the national radon maps published by Public Health England, to assess the radon levels to your property. We can also advise on appropriate monitoring of radon levels and advise on suitable works to reduce the health risks associated with high radon levels.

Does my property have wall tie failure?

Wall ties, are small steel links between the inner and outer leaves in a cavity wall. They provide strength to the wall. In certain conditions, wall ties within the outer leaf brickwork, can corrode and expand. This expansion will generate regular horizontal cracking to the outer face of the wall. We are experienced in investigating wall tie failure, and can recommend appropriate structural repairs.

What causes cracking in walls?

Cracking occurs as a result of many things. It can simply be as a result of expansion or contraction of the building materials, in which case, it would usually be viewed as cosmetic in nature and of no structural significance. However, it can also develop due to subsidence, poor design, wall tie failure, alterations to the building, over stressing to name a few. In these cases, repair works are usually required. We can provide schedules and specifications for these repairs, to ensure future stability.

When do I need to notify my insurance company?

The cost of repairs to your property, required as a consequence of subsidence, are generally covered by most domestic property insurance policies. When you notice cracking to your property, it is always advisable to appoint a Chartered Structural Engineer to assess the situation. Once you have received a structural engineer’s report concluding that subsidence has affected your property, we would recommend you notify your insurance company. They will then appoint a Loss Adjuster to review your claim, and engage with your structural engineer. We can support you from start to finish of your claim.

How can a Structural Engineer help me?

If you are buying a property, or selling a property, a structural engineer can provide you with a clear, concise report on the structural condition of the property. This may be simply to give you peace of mind on what may be the most important transaction of your life, or it may be in response to a mortgage surveyor’s report, where a potential structural defect has been highlighted. Our engineers are passionate about their work and will provide you with all the support that you require.

What is party wall agreement and do I need one?

Your works may fall under the regulations of the Party Wall Act 1996 if you are building a wall up to or astride the boundary with a neighbouring property, undertaking work to an existing wall or excavating near a neighbouring building. It is recommended to speak to a party wall surveyor if you are in doubt.

Can you reduce steel size and weight?

This will depend on many design factors and parameters and there is definitely no one set answer. For example a solution to reduce beam weight might be done by choosing two lighter beams instead of one beam or by changing architectural layout and inserting a column somewhere along the span of the beam or by changing the structural layout of the beams, etc. The options can be endless so best to discuss specific requirement with the project engineer with open mind that each project is different and solutions can vary from project to another.

I want to knock a hole in the wall that separates the dining room and kitchen to create an open plan kitchen/ dining area. What do I need to do?

Please speak to a structural engineer first before making any changes or starting any building work. The engineer can advise whether the wall is load bearing.

I want to knock down a wall in my house and I am not sure if it is load bearing

It is advisable to consult a structural engineer before doing any work. The engineer can guide you through the process and make necessary assessment in finding out whether it is a load bearing wall.

When can I start work?

You can start work once you have the complete design package, necessary agreements such as; planning permission, party wall agreement (if applicable), free holder consent (if applicable), finance, building control or NHBC if required in advance and of course once you selected a suitable reputable building contractor you are happy with.

Who submits the building control application?

Usually this is done by the architect or if required, the engineer.

Will your structural report be accepted by the bank and mortgage provider?

The reports can be done by a qualified UK chartered engineer (MICE or IStrcuctE) as required. Whilst this should be enough, you should also check with the provider what qualifications they are looking for to be extra sure.

What is the difference between subsidence and settlement?

Often mixed up, subsidence is movement of the ground that supports your property brought about by numerous actions, such as coal mining, clay shrinkage, collapse of underground caverns, and underground watercourses. Settlement is simply the ground below your building adjusting to the weight of the building sitting on it. Our engineers recognise the difference, and can establish if this movement is progressive subsidence or simply initial settlement.

Can you confirm whether the cracks are a subsidence problem?

Cracks in walls, ceilings and floors are caused by several different reasons. Depending on the size, exact location and frequency of the cracks, the risks associated can vary substantially. Subsidence or movement of foundations can often cause cracking and structural damage to the building above. There are often a variety of causes for these movements and the investigation and remediation can vary based on the cause and associated risk.

Do you provide architectural design services?

No, we do not provide architectural design services, but we are happy to recommend an architectural firm suitable for your project if required.

Can you recommend a good builder?

Yes, we have a list of reputable building contractors and could potentially make a recommendation for your specific project.

Does Bolt Structures Limitedcarry out building works?

No, we only provide consultancy services. However, we have a list of reputable building contractors and could potentially make a recommendation for your specific project.

Are you insured?

Yes, we carry professional indemnity insurance with a limit of £2m, which covers our advice, designs, calculations and reports.

Are you qualified?

Yes, we are qualified structural & civil engineers with UK experience.

How and when do I make payment?

Payment terms depend on the value of the project, but generally a 50% deposit is required prior to design. The forms of payment we accept are online bank transfers, cheques or cash. Final payments should be made on receipt of our invoice.

Will you answer queries raised by the builder during construction?

Yes, we are happy to answer relevant queries about our design to facilitate the construction process.

Will you answer building control queries?

Yes, we answer building control queries as part of our fee and we have 100% building regulations approval.

Why choose Bolt Structures Limited?

The answer is simple :-

  • 100% compliant with building regulations. We comply with part A of building regulations.
  • Fully qualified and experienced. Your projects will be handled by an engineer who has extensive previous experience.
  • Transparent fees. Our quotes are carefully constructed to avoid additional fees at later stages of design.
  • Practical and efficient designs. We consider economy in our designs.
  • Clear advice. Save time by hearing clear English with no Jargon.
  • A Team, not one individual – No one person has all the skills you need – so you get the power of a team. All our designs are cross
    checked internally.

What areas do you cover?

We currently cover London, the Home Counties, and West Midlands

Where are you based?

We are based in Harrow, London.

How long does the site visit take?

This depends on many factors such as the type and size of the project as well as the extent of issues we need to assess. For example a 3-4 bedroom house will take approximately 1 hour.

Will you carry out a site visit for my project?

Yes, unless dictated otherwise. It is good practice to carry out a site inspection and collect as much information as possible about the project in order to provide the best possible design solution and avoid unknowns that could lead to costly and complicated design and construction process.

How fast can you turn around a project?

This is dependent on the size and complexity of a project and on the supply of information from relevant parties. We always try to deliver projects quickly, but timescales will always be discussed. Typically for a domestic extension/loft conversion for a 2-bedroom house this can take 10 working days from the initial site visit. Structural reports will be concluded within 5-10 working days following inspection.

How fast can you give me a quote?

Quotes for domestic projects can be given within a day or two. For larger or more complex projects we may need more time to conclude the assessment.

What information do you need to do design work?

Usually a full set of architectural drawings (plans, elevations and sections) is a good solid way to start. Other information may be required such as tree reports, soil reports, drainage reports, historic reports such as original drawings etc but these can be discussed individually for each project.

What information do you need to supply a quote?

Full property address, full set of architectural drawings (or floor plans) and project brief. We will then review the information and if anything else is required for us to provide a quote, we will let you know.

How much does our structural engineering service cost?

The cost will vary considerably depending on factors such as the project size, complexity and the number of parties involved. For example, a simple beam design will cost a few hundred pounds, whereas the cost for full refurbishment consisting of a loft conversion, extension and taking out internal load bearing walls can start from one and a half thousand pounds and upwards.

What does Bolt Structures Limited do?

Bolt Structures Limited provides engineering services for the refurbishment sector and new build projects throughout London, Home Counties.We are involved in a range of projects including domestic conversions, extensions and refurbishments as well as in the commercial and retail sectors. The construction value of a typical project would range between £10,000 to £3,000,000. The company has 100% building regulations approval. Our services include but not limited to:

  • Structural design drawings and calculations
  • Structural reports, Method Statements
  • Temporary works design

How much does it cost to get a structural engineer report UK?

The cost of a report should range depending on what is required from the engineer to inspect and report on. Usually for a London domestic property of 3 bedrooms you should expect a range of between £650+VAT – £950+VAT. For larger domestic properties such as 5 bedrooms detached houses expect the cost to rise up to £1500+VAT or more depending on scale.

What is the difference between a structural engineer and a surveyor?

A structural engineer can help with specifying structural elements required for altering an existing building or creating a new one. This can be done by doing drawings & calculations to support the build and comply with building regulations (part A – Structure). A structural engineer can also prepare a structural report as a specialist on structural defect issues such as subsidence, movement and cracking etc. A surveyor role can be diverted to carry out general building surveys on the overall condition of the building, provide valuations or act as an expert witness to resolve a dispute. Party wall surveyors can also help with sorting out party wall disputes and ensuring compliance with party wall act.

Should I have a structural engineer inspection?

If you have concerns about a structural defect within your property then you should hire a structural engineer to visit and inspect your property and advise you whether the defects are ongoing, historic and whether they are serious or minor. Also if you are preparing to embark on structural works within your property such as creating an extension or loft conversion or even knocking down walls or chimney breasts, it is always recommended to hire a structural engineer to make an inspection and prepare the necessary drawings & calculations to confirm which walls are structural and how to create support required to achieve your aspirations.

Will the structural surveyor examine the loft?

Surveyors will inspect the loft and pay particular attention to the roof. The roof is often where structural problems hide, particularly as this is an area of the building not typically shown to buyers.

Will the structural surveyor examine cupboards?

Surveyors will open cupboards to check for unseen damage or defects that might worsen. The surveyor will take care of the contents of the cupboard and ensure they have the owner’s consent before moving anything.

Will the structural surveyor look at the boiler?

No, this is not part of the structure thus outside the scope of the structural survey.

Will they look for Japanese knotweed?

A surveyor will look around the property and note the presence of Japanese knotweed as part of a structural survey.

How long will the report take?

Depending on the size of the property and what we find, a structural survey can take anywhere between an hour or two on site to complete the report. The report can take 5 to 10 working days to complete. The timing will vary depending on access and the property size.

Will the structural surveyor need to shift furniture?

Inspections do not involve moving furniture, fixtures, fittings, or the use of invasive procedures. The purpose of the Inspection is to determine so far as is reasonably practicable whether the structure has any visually evident defects that may compromise its stability. If any intrusive measures are required then the surveyor will raise the request accordingly.

What is a structural survey?

Bolt Structures Limited are undertaken in order to report on structural defects such as cracks in walls, damage caused by water or subsidence / movement of foundations etc. The initial report will usually be based on a visual inspection of the associated area of concern. If further intrusive investigations are required to identify the cause and condition of the defect/s, we will also advise on this.

How do you find a structural engineer?

Since you have managed to find us then you are on the right path already! A structural engineer can be found through word of mouth or online search, business directories etc.  We can help you by starting to discuss your project and supply a quote if required.

How did my neighbours do it?

Each project is different. Whist neighbouring houses can appear the same, small variances can make a difference in how the design should be approached. We tailor each design to suit your preferences.

Do I need Planning permission?

We would recommend you seek the advice of your local council and an Architect or Planner.

Do I need an Architect?

If you are planning an extension, loft conversion, full internal remodelling or a new build then yes you will need an architect. Unless your project is limited to removal of one or few walls within your property then you may not need one.

What are the next steps after I employ a structural engineer?

A site inspection will take place and a dialogue will be opened with the architect and the client to finalise the project brief. Upon delivery of the full design package and receipt of relevant statutory approvals construction can commence. Your structural engineer will provide support through to project completion.

Do you produce safe designs, accurate drawings and calculations?

Yes, each design is tailored to meet your project’s requirements, following a site inspection. We take into account relevant design codes, building regulations and CDM regulations.

When would I need a Structural Engineer?

It is recommended to engage with a structural engineer as well as an architect at building control design stage, well ahead of construction. In other cases, particularly for new builds or basement conversions, a structural engineer might be required to carry out a feasibility study before submitting a planning application. The architect can also advise the client on when a structural engineer is required.

Why do I need structural calculations for my project?

If construction work is proposed in a project, involving altering the existing structure, adding significant loads or building a new structure, then you will need structural calculations. These calculations and drawings will need to be produced by a qualified structural engineer in order to comply with building regulations and other statutory regulations. Not all projects require calculations, but it is recommended that you speak to an engineer to seek advice.

Do I need a structural engineer for my home project?

If construction work is proposed in a project, involving altering the existing structure, adding significant loads or building a new structure, then you will need a structural engineer. If you are unsure whether the alterations are structural (such as whether a wall is load bearing or if removing a chimney has structural implications) then you will also need advice from a structural engineer.

What does a structural engineer do?

A structural engineer is responsible for the design of a building or structure, providing the calculations and drawings relevant to assure structural integrity throughout construction and life cycle. This ensures buildings and structures are safely built and comply with Part A of the Building Regulations.