Insulation: service hero

Service

Insulation

Fabric-first retrofit: loft, cavity, internal and external wall insulation, installed to PAS 2030 standards with moisture and ventilation designed in.

PAS 2030TrustMarkCIGABBA
Book a free surveyCall 0800 999 1129

Why this matters

Cold walls, draughty rooms, and heat that disappears as fast as you produce it

Without a good thermal envelope, every heating upgrade fights a losing battle. Insulation is the single highest-impact measure in most retrofit plans, and the one most commonly done badly, with consequences (damp, mould, cold bridging) that take years to appear. Doing it properly is the difference between a house that feels different in the first week and one that develops problems in the first winter.

What you get

A warmer, quieter, lower-running-cost home, without moisture trouble

  • Targeted insulation measures prioritised by actual impact on your home's heat loss

  • Reduced heat demand, so your boiler or heat pump works less hard and lasts longer

  • Ventilation redesigned where insulation changes airflow: no mould, no condensation, no regret

  • PAS 2030 documentation and TrustMark lodgement for every measure

Our approach

Fabric-first, diagnostics-led retrofit

We prioritise the measures that change how your home feels and performs: loft, cavity, floors, and external or internal wall solutions where appropriate. Every measure is assessed against your property's construction, existing ventilation, and moisture risk before we specify.

Construction-aware assessment

Solid-wall Victorian, cavity-wall 1930s, timber-frame 1980s: each has different risks and solutions. We diagnose before we prescribe.

Condensation risk analysis

For every internal or external wall insulation project, we assess interstitial condensation risk and specify membrane and ventilation accordingly.

Ventilation designed in

Insulation changes airflow. We assess and upgrade background ventilation, extractor fans, and MVHR where needed, so you do not trade draughts for damp.

Quality detailing at interfaces

Reveals, lintels, eaves, service penetrations: the locations where most insulation failures occur. We detail them deliberately.

How it works

  1. 1

    Property assessment

    A surveyor visits to assess construction type, existing insulation, ventilation, moisture risk, and access. Photography and measurements taken throughout.

  2. 2

    Specification and quote

    A written specification covering material choices, U-value targets, ventilation upgrades, finishes, and any building control requirements. Fixed price per measure.

  3. 3

    Installation

    Depending on measure: loft insulation (half a day), cavity wall injection (half to one day), internal wall insulation (one to two weeks per room), external wall insulation (four to six weeks).

  4. 4

    Quality inspection

    Every install inspected against the specification. Thermographic check available on request for external and internal wall insulation projects.

  5. 5

    Certification and handover

    Building control sign-off (where required), TrustMark lodgement, and a full handover pack with ventilation and maintenance guidance.

Our signature honesty

Where we won’t fit it

If your cavity isn’t clear on a borescope, we won’t fill it. A damp bridge in a wet cavity is worse than the draughts it replaces. If you’re in a high-exposure coastal property, certain cavity materials aren’t appropriate and we’ll say so. If your internal or external wall insulation design doesn’t respect ventilation, we’ll redesign it until it does. And sometimes the honest answer is loft and draught-proofing first, with solid-wall insulation saved for a later phase. We’d rather tell you that on day one than ship a job that leaves you with moisture problems in five years.

The specialisms

What we install

Insulation isn’t one job. Five separate specialisms sit under the same discipline. Each is surveyed differently, each has its own moisture-risk check, and each is done by a team that does that specific work every week.

Loft insulation

The most cost-effective single upgrade most UK homes can make. Top-up to 270mm, proper eaves-ventilation detailing, boarded storage raised on insulated stilts so storage doesn’t compress the insulation underneath, and fire-safe caps over recessed downlights. We thermal-image before and after so you can see the difference on camera.

Cavity wall insulation

Dual PAS 2030:2023 certified through two independent bodies because this is one of the highest-risk retrofit measures in the UK. Every cavity job starts with a borescope inspection at multiple locations and an honest verdict on suitability. The right material for your exposure rating, around-opening detailing to avoid thermal bridges, and a 25-year guarantee.

Solid wall insulation, external (EWI)

For properties with the architectural flexibility for it. Render system or through-coloured silicone topcoat matched to the property. Scaffolding around the building for four to six weeks; no internal disruption. Full condensation-risk analysis and vapour-control detailing. The single biggest single-measure carbon reduction a solid-walled home can make.

Solid wall insulation, internal (IWI)

For properties where external insulation isn’t appropriate: listed buildings, conservation areas, or owners who want the external character preserved. Done room by room, with full hygrothermal modelling to ensure the wall can still breathe. Redecoration and some furniture disruption during works. Electrical sockets and radiators carefully re-fixed.

Underfloor & draught-proofing

Suspended timber floors can lose significant heat, often the coldest bit of a Victorian terrace. Rigid board between joists, properly detailed at edges, ventilation preserved below. Draught-proofing around windows, doors, letterboxes and floorboards is often the highest-ROI retrofit intervention of all, and we include it on every fabric survey as standard.

Key benefits

Genuine comfort upgrade

Warmer internal surface temperatures, fewer cold spots, less draught, most noticeable in the rooms you use most.

Lower heat demand

Typical whole-house insulation upgrade reduces heat demand by 20–40%, making any heating system cheaper to run and smaller to size.

Noise reduction as a bonus

External wall insulation and some internal systems also reduce external traffic and neighbour noise, particularly in terraced properties.

No-regret retrofit sequencing

Insulation first, heating second, generation third: the order that delivers the best lifetime cost and comfort result.

The certifications behind this work

For this service specifically, we operate under the following industry accreditations. Each one has passed audit and is verifiable with the issuing body.

  • PAS 2030
  • TrustMark
  • CIGA
  • BBA

Frequently asked questions

Which insulation measure should I do first?+

For most properties, loft insulation (if under 250 mm) or cavity wall insulation (if empty and suitable) are the lowest-hanging fruit: affordable, fast, and impactful. External or internal wall insulation for solid-walled properties is higher cost but transformative. We prioritise based on your property's actual heat loss breakdown, not a national average.

Is internal or external wall insulation better?+

External wall insulation is thermally better (no cold bridges at intermediate floors) and preserves your internal space, but requires planning consent in some areas and changes your property's external appearance. Internal wall insulation is cheaper and faster but reduces room size by around 100mm per wall and requires careful detailing around windows and sockets. We explain the trade-offs for your specific property.

Will insulation cause damp or condensation?+

Not if it is done properly. Damp problems after insulation almost always trace to inadequate ventilation: insulation reduces air leakage, so ventilation must be actively designed. We assess and upgrade ventilation as part of every internal or external wall insulation project. Cutting corners here is why insulation has a poor reputation in some quarters.

Is cavity wall insulation still safe and effective?+

For suitable properties, yes. Bonded bead injection has a thirty-year track record and a CIGA guarantee. Unsuitable properties (exposed coastal, defective render, narrow or blocked cavities) are a different matter. Our surveyor inspects the cavity with a borescope before recommending injection. If it is not suitable, we say so.

What about a Green Deal or grant funding?+

The Boiler Upgrade Scheme (BUS) requires your EPC to be free of outstanding loft and cavity insulation recommendations, so insulation is often a prerequisite for a heat pump grant. Other grant schemes come and go with government policy; we advise on what is currently available during your survey.

How disruptive is wall insulation work?+

Cavity injection is very low disruption: holes drilled in mortar, bead injected, holes repointed. Half a day per house. Internal wall insulation is more involved (one to two weeks per room, furniture removal and redecoration required). External wall insulation is the most involved (four to six weeks, scaffold around the property), but does not affect internal life at all.

Ready to talk about insulation?

Book a free survey. A qualified engineer will visit, assess your property honestly, and send a written recommendation within five working days. No obligation.

Book a free surveyCall 0800 999 1129

Insulation isn't sexy, but the numbers are

Often the best-value retrofit measure.

£800–£2,200

for a typical 3-bed semi cavity fill, including moisture-risk assessment and 25-year CIGA warranty.

What moves it up

Rendered or clad walls: drilling and patching

What holds it at base

Standard brick exterior

What brings it down

Simple access, clean wall

What moves it up

Existing insulation issues: partial fill to remove

What holds it at base

No existing fill

What brings it down

Cavity confirmed clear on borescope

What moves it up

Moisture remediation needed before fill

What holds it at base

Moisture-risk assessment passes

What brings it down

Dry, textbook cavity

A free survey is how we turn this range into a fixed price. We'll never ask you to commit before the written plan is in your hands.

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Prices last updated: 25 April 2026. We update quarterly.

When insulation is not what your home needs

We say no more than the industry average.

Most UK homes benefit from some kind of insulation work. A few don't. And the wrong insulation job in the wrong property can cause real damage.

We'd say no to a cavity fill when:

  • The borescope shows existing damp, rubble, or poor construction
  • The external brickwork is cracked or porous (would absorb water and transmit it inward once insulated)
  • The property is in a high-wind-driven-rain zone with solid or partly-solid walls
  • A previous cavity fill has failed and hasn't been removed

We'd say no to internal wall insulation (IWI) when:

  • The property is being redecorated heavily and the room sizes would be reduced problematically
  • The existing wall surface has serious damp issues untreated
  • The cost-per-m² exceeds the likely energy saving over 10 years

We'd say no to external wall insulation (EWI) when:

  • The property is in a conservation area that would reject the planning application
  • The adjacent properties aren't insulating too (creates awkward junctions)
  • There are existing structural issues in the external wall that need addressing first

Roughly 20% of the insulation enquiries we survey end in a “no, here's the alternative” conversation.

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