Construction compliance guide

What RAMS Do You Need for a House Extension?

A practical guide to the risk assessments and method statements you need for a typical house extension. Covers every phase from excavation to finishing, with specific controls for each hazard.

Nicola Dobbie·Founder, The Site Book

TL;DR

• A house extension involves significant hazards: excavation, working at height, structural alterations, services strikes, manual handling, and potentially asbestos.
• You need RAMS covering each major phase of the work. A typical extension might require five to eight RAMS documents.
• You also need a construction phase plan (CPP) — CDM 2015 applies to domestic projects.
• Every RAMS must be site-specific. Generic templates will not cover your particular site constraints, neighbours, or conditions.
• Clients and architects increasingly ask to see RAMS before work starts — it shows professionalism and protects you legally.

In this guide

Why do you need RAMS for a house extension?

A house extension is not a low-risk job. It typically involves excavation (foundation trenches that can collapse), working at height (scaffolding, roof work), structural alterations (removing load-bearing walls, installing steel beams), heavy manual handling (blocks, lintels, steels), power tool use, and work near live services (gas, electric, water, drainage). Any one of these activities could cause serious injury or death if not properly planned and controlled.

Under the Construction (Design and Management) Regulations 2015, every contractor must plan, manage, and monitor construction work so it is carried out without risks to health and safety. A RAMS (Risk Assessment and Method Statement) is the standard way to evidence this planning. It shows that you have identified the hazards, evaluated the risks, put control measures in place, and planned the sequence of work step by step.

Beyond the legal duty, there are practical reasons. A good RAMS helps you think through the job before you start. It forces you to consider access constraints, sequence of trades, temporary works requirements, and what could go wrong at each stage. It also protects you commercially — if a dispute arises with the client, or if a subcontractor causes damage, the RAMS is evidence that you planned the work competently.

What are the excavation and groundworks hazards?

Excavation is one of the most dangerous phases of an extension project. Foundation trenches for a domestic extension are typically 600mm to 1,000mm deep, and deeper where ground conditions require it. At these depths, trench collapse is a real risk — unsupported trench walls can collapse without warning, burying or crushing the person inside.

Your excavation RAMS should cover: trench support requirements (hydraulic shores or battered-back trenches where width allows), spoil management (stockpiled at least 2m from the trench edge), safe access in and out of the trench (steps or ladder, not climbing on the trench supports), inspection of the trench at the start of each shift and after heavy rain, and an exclusion zone around the excavation to keep other workers and the public at a safe distance.

Other groundworks hazards include: the mini digger tipping or striking an operative (maintain a safe distance from the swing radius, use a banksman for reversing operations), contact with underground services (covered in detail below), water ingress (have a pump on standby and a procedure for dewatering), and proximity to existing foundations (the structural engineer should confirm the minimum distance and specify any underpinning requirements).

Remember that the HSE guidance on excavation (HSG150) requires excavations to be inspected by a competent person before any operative enters, at the start of each shift, and after any event that might affect stability (heavy rain, adjacent vehicle movements, nearby excavation work).

What does the scaffolding and working at height RAMS need to cover?

Most house extensions require scaffolding for the superstructure and roofing phases. Falls from height remain the single biggest killer in UK construction — the HSE reports that falls account for around 40% of construction fatalities every year. Even on a single-storey extension, a fall from scaffold at eaves height (typically 2.4m to 3m) can cause life-changing injuries.

Your RAMS should specify: who will erect the scaffold (it must be erected by CISRS-carded scaffolders or, for a basic scaffold tower, PASMA-trained operatives), the scaffold specification (tube and fitting, system scaffold, or scaffold tower), edge protection requirements (double guard rails, toe boards, and brick guards on all open edges), the inspection regime (before first use, every seven days thereafter, and after any event that could affect stability such as high winds), and the scaffold inspection register.

For domestic extensions, also consider: proximity to the neighbour’s boundary (you may need a licence to place scaffold on their land or on the public highway), access for the homeowner (if the scaffold blocks a door or window, provide an alternative route), loading limits (do not overload scaffold platforms with bricks and mortar), and the procedure for modifying or dismantling the scaffold (only by competent persons).

If any roofing work involves fragile materials (roof lights, asbestos cement sheets on an existing structure), the RAMS must specifically address fragile surfaces — crawling boards, fall arrest nets, or exclusion zones below fragile areas.

What RAMS do structural alterations and demolition require?

Most house extensions involve some form of structural alteration to the existing building — typically removing a section of the rear wall to create the opening between old and new. This is high-risk work. If the temporary support fails, the wall above the opening can collapse, and the consequences are potentially fatal.

Your RAMS should cover the full sequence: installing temporary support (Acrow props, needles, or a goal-post arrangement as specified by the structural engineer), the demolition of the existing wall section (hand demolition in a controlled sequence, not knocking it out with a sledgehammer), installation of the permanent steel beam or lintel, and the procedure for removing temporary support once the permanent structure is in place and has gained adequate strength.

The critical controls include: a temporary works design from the structural engineer specifying the propping arrangement, load-bearing capacity, and minimum curing times; an exclusion zone during demolition (nobody on the other side of the wall); dust suppression (wet cutting, extraction, or RPE); and a clear sequence that ensures the structure is never left in an unstable condition overnight or during a break.

If the extension involves demolishing an existing lean-to, conservatory, or outbuilding, the RAMS should also address: disconnection of services (gas, electric, water) before demolition begins, identification of any asbestos-containing materials (see below), and waste management (skips, segregation, dust control).

What about asbestos on a house extension project?

Asbestos is present in a huge number of UK homes built or refurbished before the year 2000. On a house extension project, you are likely to disturb existing building fabric — removing walls, ceilings, roofing materials, flue pipes, soil pipes, and floor coverings. Any of these could contain asbestos.

Before any work begins on the existing structure, you should commission a refurbishment and demolition (R&D) asbestos survey from a UKAS-accredited surveyor. This is a legal requirement under the Control of Asbestos Regulations 2012 for any work that involves disturbing the building fabric. A management survey (the type done for building occupation) is not sufficient — you need the more intrusive R&D survey.

Common locations for asbestos in domestic properties include: textured coatings (Artex) on ceilings, asbestos cement roof sheets and soffits, asbestos insulating board in airing cupboards and around boilers, vinyl floor tiles and their adhesive backing, flue pipes, and gaskets around older boilers. If asbestos is found, it must be removed by a licensed contractor (for high-risk materials) or managed safely under your RAMS (for lower-risk materials like asbestos cement in good condition).

Your RAMS should reference the survey results and describe the controls for any asbestos-containing materials that will be disturbed during the works. If no survey has been done and the property pre-dates 2000, you must assume asbestos may be present and commission a survey before proceeding.

How do you avoid hitting underground services?

Striking an underground gas main, electricity cable, or water main during excavation can cause explosion, electrocution, or flooding. On a domestic extension project, you are excavating close to the existing house, where services enter the property. Gas mains, water supply pipes, electricity cables, drainage, and telecoms cables may all run through the garden.

The HSE guidance HSG47 (Avoiding Danger from Underground Services) sets out the standard approach. Your RAMS should include the following controls:

Obtain utility plans from the client, utility companies, or a plan provider before any excavation begins
Carry out a CAT (Cable Avoidance Tool) and Genny scan of the excavation area. The scan should be carried out by a trained operative and the results marked on the ground with spray paint
Dig trial holes by hand within 500mm of any detected service. Never use mechanical excavation within 500mm of a known service
Brief all operatives on the locations of known services before excavation starts. Mark service routes with marker posts or barrier tape
Have emergency contact numbers for all utility companies readily available on site. Know the procedure for each type of service strike: gas (evacuate, call National Gas Emergency on 0800 111 999), electricity (do not approach, call the distribution network operator), water (isolate if possible, call the water company)

Be aware that utility plans are not always accurate. Services may have been diverted or added since the plans were drawn. The CAT scan will detect most metallic services, but it may miss plastic pipes. Always treat the ground as if it contains unknown services until proven otherwise.

How should RAMS address manual handling on extension projects?

House extensions involve a lot of heavy lifting: blocks, bricks, bags of cement, sand, lintels, steel beams, roof timbers, and plasterboard sheets. Manual handling injuries are one of the most common causes of time off work in construction, and domestic sites often have poor access that makes the problem worse — narrow side gates, steps, uneven ground, and long carries from the skip or delivery point to the work area.

Your RAMS should apply the hierarchy of controls to manual handling. First, eliminate where possible: can materials be delivered directly to the work area by crane offload or conveyor? Can the mini digger move pallets of blocks from the front to the rear? Second, reduce: use lighter-weight blocks (thermalite rather than dense concrete where the structural engineer permits), smaller bag sizes, and half-loads. Third, plan team lifts for heavy items: steel beams, ridge beams, and long timbers should always be a team lift with a minimum number of people specified. Fourth, train: all operatives should understand safe lifting technique.

Specific controls for common items: standard concrete blocks (20kg each) should be carried no more than two at a time. Plasterboard sheets (typically 25–30kg) should be carried by two people. Steel beams (often 80–200kg+) must be lifted mechanically — by telehandler, mini crane, or chain block. Bags of cement (25kg) should be lifted from pallet height, not from the ground, and carried no further than necessary.

Consider the access route. If materials have to pass through a 900mm side gate and down three steps to the rear garden, plan for this. Can a section of fence be temporarily removed? Can a conveyor belt be used? Can the delivery be scheduled for a specific day when the access route is clear? Your RAMS should describe the access route and the controls for getting materials to the work area safely.

What other hazards should your extension RAMS cover?

Beyond the major hazards above, a house extension RAMS should also address several other risks that are easy to overlook:

Dust and silica exposure

Cutting blocks, bricks, concrete, and tiles generates respirable crystalline silica dust, which causes silicosis and lung cancer. Your RAMS should specify wet cutting or extraction ventilation for all masonry cutting, and FFP3 masks as a last resort. The HSE has been running targeted enforcement campaigns on construction dust since 2019, so expect this to be checked if an inspector visits.

Noise

Power tools, disc cutters, breakers, and compactors all generate noise levels that can cause permanent hearing damage. Your RAMS should identify the noisy activities, specify hearing protection where exposure exceeds 85 dB(A), and consider the neighbours — planning conditions often restrict noisy work to certain hours.

Electrical safety

All portable power tools should be 110V (via a transformer) or battery-operated. If 240V tools must be used (e.g. for testing), an RCD must be used. Temporary electrical supplies should be installed by a qualified electrician. The first-fix electrical work itself is notifiable under Part P of the Building Regulations.

Fire

Hot works (soldering, lead work, bitumen heating) require a hot work permit and a fire watch period of at least 60 minutes after works are complete. Flammable materials (timber, insulation, adhesives) should be stored away from ignition sources. At least one fire extinguisher should be on site at all times.

Public and client safety

The site is in someone’s home. The client, their family, visitors, and neighbours may all be nearby. The RAMS should describe how you will separate the work area from the living space (temporary partitions, locked access gates, signage), how you will manage deliveries on a residential street, and how you will prevent unauthorised access — particularly by children.

Weather

Domestic projects are exposed to the weather. High winds affect scaffolding and lifting operations. Rain affects excavation stability and slip risk. Frost affects concrete curing and mortar joints. Your RAMS should describe the weather thresholds that will trigger a stop-work decision — for example, no lifting operations in winds above 30 mph, no excavation work during or immediately after heavy rain without re-inspection.

Do you need a CPP for a domestic extension?

Yes. CDM 2015 applies to all construction work, including domestic projects. Regulation 12 requires the principal contractor (or, where there is only one contractor, that contractor) to prepare a construction phase plan before the construction phase begins.

For a domestic extension, the CPP can be relatively straightforward. It should cover: a description of the project and site, the management structure (who is in charge, who is the first aider, who to call in an emergency), site rules (working hours, PPE requirements, parking, access), welfare facilities (portaloo, hand-washing, rest area), emergency procedures (first aid, fire, service strikes), and a summary of the main risks with references to the individual RAMS that cover them in detail.

The CPP does not need to be a 30-page document for a domestic extension. The HSE expects it to be proportionate. Six to eight pages covering the essentials is usually adequate. The key is that it is specific to the project — not a generic template with the project name changed.

The Site Book can create both the CPP and the individual RAMS for your extension project from a single project description. The CPP wizard asks about your project type and adjusts the level of detail accordingly, giving you a domestic-appropriate CPP without the commercial-project bloat.

What might the client or architect ask for?

Homeowners are becoming more informed about construction safety. Many will research CDM 2015 before their project starts, particularly if they have an architect or project manager advising them. Here is what you might be asked to provide:

A construction phase plan (CPP) covering the whole project
RAMS for each major phase of the work (groundworks, superstructure, roofing, first fix, second fix)
A copy of your employer’s liability insurance certificate
Evidence of competency: CSCS cards for all operatives, SMSTS for the site supervisor, CISRS for scaffolders
An asbestos survey report for the existing building (which you should commission regardless)
A waste management plan showing how construction waste will be disposed of responsibly
Proof of public liability insurance, especially if the site is near a public footpath or road

Being able to provide these documents promptly and professionally sets you apart from competitors who cannot. It builds trust with the client, gives the architect confidence in your competence, and protects you if anything goes wrong. The Site Book creates all the safety documentation you need — CPP, RAMS, site induction pack — from your project description, so you can respond to these requests in minutes rather than days.

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Frequently asked questions

Common questions about RAMS for house extension projects.

Do I legally need RAMS for a house extension?

UK law does not specifically require a document called a ‘RAMS.’ However, the Management of Health and Safety at Work Regulations 1999 require every employer to assess risks and plan safe systems of work. The Construction (Design and Management) Regulations 2015 require every contractor to plan, manage, and monitor construction work so it is carried out without risks to health and safety. A RAMS is the standard way the construction industry meets these duties. If the HSE investigates an incident on your extension project and you cannot demonstrate that you assessed the risks and planned the work properly, the absence of written documentation will count against you. For any work involving significant risk — and a house extension involves plenty — you should treat RAMS as essential.

How many RAMS do I need for a typical extension?

It depends on how you organise the work. Some builders produce a single comprehensive RAMS covering the entire extension project. Others produce separate RAMS for each phase: groundworks, superstructure, roofing, first fix, second fix, and so on. If multiple subcontractors are involved (bricklayer, roofer, electrician, plumber), each will typically produce their own RAMS for their scope of work. As a rough guide, a typical two-storey extension with a main contractor and three or four subcontractors might generate five to eight individual RAMS documents. The key is that every significant activity is covered and every significant hazard is addressed.

Does the client or architect need to see the RAMS?

There is no legal obligation for a domestic client to review your RAMS, but increasingly, clients and their architects or project managers ask to see them. It demonstrates professionalism and reassures the client that you take safety seriously. Some architects will specifically request RAMS as a condition of their contract with you, particularly for larger or more complex domestic projects. If you are working under a JCT or FMB contract, there may be a contractual requirement to produce and submit RAMS. Even if nobody asks, having a RAMS protects you. If a dispute arises or an incident occurs, the RAMS is evidence that you planned and managed the work competently.

Do I need a CPP as well as RAMS for a house extension?

Yes. CDM 2015 applies to all construction work, including domestic projects. The construction phase plan (CPP) is the overarching management document that sets out how health and safety will be managed across the entire project. The RAMS sit underneath the CPP — they cover individual activities in detail. For a domestic extension, the CPP can be relatively simple: project description, management structure, site rules, welfare arrangements, emergency procedures, and a summary of the main risks with references to the relevant RAMS. The Site Book can create both the CPP and the individual RAMS from your project description, so you do not have to produce them separately.

What if I am a sole trader doing the extension myself?

The duties under CDM 2015 and the Management Regulations apply to you just the same as they apply to a limited company with fifty employees. As a sole trader, you are both the employer and the worker, and you are the contractor under CDM. You must assess risks, plan safe systems of work, and provide welfare facilities. Producing a RAMS is the recognised way to evidence this planning. If you employ or engage any other workers (including subcontractors), you also have duties towards them under the Health and Safety at Work etc. Act 1974. The RAMS demonstrates that you have thought through the hazards and put controls in place — protecting both yourself and anyone else on the project.

Can I just download a template from the internet?

You can, but a generic template is unlikely to meet the legal standard of ‘suitable and sufficient.’ A template will not mention the overhead power line behind your specific site, the shared access with the neighbours, the asbestos survey results for the existing building, or the fact that the client’s children play in the garden every afternoon. Every RAMS must be tailored to the specific job and site. A template can give you a structure to follow, but you must fill it with site-specific content. The Site Book takes a different approach: instead of handing you a blank template, it asks you to describe your job and creates a RAMS tailored to your project, so the site-specific detail is built in from the start.

How The Site Book helps

• Creates extension-specific RAMS covering all typical hazards from excavation to finishing
• Hazard library pre-loaded with domestic extension risks — scaffolding, structural openings, services, asbestos, manual handling
• CPP wizard creates a proportionate domestic construction phase plan alongside your RAMS

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