How to hire
Match the job to the trade first. An insulation installer owns loft quilt, cavity fill, internal and external wall insulation and the ventilation around them — not solar panels or batteries, which sit in the renewables trade, and not structural roofing, which sits with a roofer. Several firms in this ranking lead with those neighbouring trades, so read each card for what the firm actually does. When you first enquire, say your wall type and the age of your home, which rooms suffer, and whether the loft is boarded or lived in [1] [2].
Check grants before you agree to pay. The Great British Insulation Scheme mostly funds single insulation measures such as cavity, loft or solid wall insulation, reaching beyond low-income households to homes rated D to G in lower council tax bands, while ECO4 takes a whole-house approach [6]. Contact an obligated energy supplier, even one you are not with, and an assessor visits your home to decide the measure after a retrofit assessment [6]. Every installer on the scheme must be a TrustMark-registered business, so ask for registration credentials and check them on the TrustMark website [6].
Check the firm on the registers before you book. Search the TrustMark find-a-tradesperson service for the business name and confirm the number yourself rather than taking a logo at face value [7]. The National Insulation Association lists installer members you can search by postcode, town or county [8]. For cavity wall work, ask whether the installer is registered to issue the long guarantee behind the job, and for spray foam or board products ask for the current product certificate number and check it on the certificate database yourself [4] [9]. Ask for public liability insurance details and a recent local reference you could verify.
Make cavity wall jobs pass a suitability test. Not every wall wants filling: exposure, existing damp, narrow or rubble-filled cavities and timber frames can rule it out, so expect the installer to inspect the walls, check the age and construction, and talk ventilation before quoting [1]. Agree what happens to air bricks, flues and recessed lights. Get the guarantee behind the work in writing: the standard independent guarantee runs twenty-five years against defects in materials and workmanship, caps remedial work, and passes to later owners — keep the certificate with your house papers [4] [5].
Get two or three itemised written quotes on the same written scope, so you compare like with like, and get each as a quote rather than an estimate: a quote is a fixed promise you can hold the firm to [10]. Each quote should separate labour, materials and VAT, and name the measure, the material and its thickness, the area covered, access and scaffolding, making-good, ventilation steps, the start date and payment stages — a deposit for materials is normal, while full payment before completion is not. Treat an outlier, far above or below the rest, as a question rather than a bargain.
Close out with paperwork you can find later. For cavity wall insulation, file the guarantee certificate with its unique number; for grant-funded work keep the assessment and the energy supplier paperwork; for every job keep the quote, invoice and any product certificates together [4] [6] [10]. Photograph the finished loft depth or wall finish before you pay the balance. If a fault appears, tell the installer straight away and give them the chance to put it right — the guarantee route expects the installer first, with a written note to the guarantor if the matter sits unresolved after two months [4].
Telford mixes two kinds of street. The new town was designated around Dawley in the early sixties and grew by folding in Wellington and older townships alongside new estates, so cavity-wall homes stand a short drive from solid-wall terraces and Gorge cottages [16]. Older streets in Wellington, Dawley and Madeley, and cottages around Ironbridge, most often hold the solid-wall homes that need specialist surveys, while newer estates such as Lawley tend toward standard cavity and loft jobs. Send your street and home age in the first message, and expect different questions back.
External wall insulation changes how your home looks from the street, so planning rules bite before you agree anything. Outside special areas it can go ahead where the finish resembles the existing walls, but cladding in a conservation area needs permission, and significant works to a listed building need consent inside or out [11]. Telford and Wrekin holds eight conservation areas, including Wellington and the Severn Gorge, and every dwelling in the Gorge's World Heritage Site sits under an Article 4 Direction that can pull minor works into permission [12] [13]. Check the council's map for your street and raise it in the first enquiry.
From first contact to sign-off, expect one course: photos and home details from you, an in-person survey, a fixed written quote, the work itself, then inspection and payment. The quote should name the measure, material and thickness, the rooms or walls covered, access and scaffolding, making-good, ventilation steps, start date, payment stages and the VAT position, each on its own line [10]. The closing pack should hold the invoice, any product certificates, the guarantee certificate with its number for cavity work, and the assessment letters for grant-funded jobs [4] [6]. Photograph loft depth or wall finish before the balance leaves your account.
Pricing
As of autumn 2026, rough Telford ranges run like this: topping loft insulation up to the recommended depth costs around £600 where some insulation already lies, or around £750 from bare joists, for a typical home in Great Britain [2]. Filling the cavity walls of a typical home costs around £2,200 and should pay for itself within five years through lower heating bills [1]. These are national averages, so your Telford quote moves with the size and shape of your home.
Solid walls cost far more to treat: insulating them inside or out typically runs between £12,000 and £15,000 [3]. Conservatory roof insulation and raised loft boarding with ladders and lights are quoted per job across this round, with no published rate cards to lean on — describe the room and agree the figure in writing before boards lift.
Ground floors come next for homes that already hold loft and wall insulation. Insulating a suspended timber floor typically costs between £1,400 and £2,500, with solid floors dearer, and the figure moves with floor size, material and how easily boards lift [14]. Expect around £55 a year back on energy bills in Great Britain, alongside warmer rooms underfoot [14].
Sealing gaps around doors, windows and floors is the smallest ticket here: professional draught-proofing of a whole house runs around £250, with do-it-yourself kits costing less, saving around £55 a year in Great Britain [15]. Leave vents, flues and trickle vents alone, since blocking them risks damp and stale air [15].
Access and condition move the price most: scaffolding for external wall work, lifting and refitting floorboards, clearing a packed loft, and putting right damp or crumbling render all add labour [2] [3]. If you want storage above the insulation, say so in the enquiry: the design changes to protect the quilt's depth, and so does the price [2]. Travel and parking across Telford and the state of air bricks, flues and hatches all add or subtract.
Ask whether the quote includes VAT and whether the figure is a fixed quote or an estimate, since only a fixed quote holds the price [10]. Firms in this round publish almost no example rates — shelf prices appear only on an online acoustic shop — so treat any single fixed price for a whole house with no breakdown as a question, not an answer. Get the scope in writing before work starts and keep every quote, invoice and certificate together.
Red flags
Quotes cavity wall insulation without inspecting your walls or asking the age and construction of your home [1].
Cannot give a TrustMark or trade-body registration number you can check yourself on the scheme website [7] [8].
Recommends spray foam for a roof without naming the product or showing its current certificate for your roof type [9].
Boards straight over loft quilt, compressing it flat, instead of fitting a raised system that protects its thickness [2].
Asks for full payment in cash before starting, with no written quote or terms [10].
Gives one fixed price for insulating a whole house with no breakdown of labour, materials and VAT [10].
Finishes cavity wall work with no guarantee certificate and no written aftercare route [4].
Starts external wall insulation without mentioning planning permission where your street sits in a conservation area or the Gorge [11] [12].
Offers grant-funded work but cannot name the scheme behind it or the supplier route your survey follows [6].