Design once, build once

Every fibre network is built twice: once in the design and once in the ground. When the design is right, the build runs to plan. When it is not, gaps emerge as idle crews, blocked ducts, repeat road openings and network records nobody trusts.

Design is a small share of programme cost, yet it shapes what follows: the routes civils crews dig, the cables and joints they install, the capacity left for growth, and the data the operator will rely on for decades.

This paper draws on Entegro’s design work for Tier 1 and national fibre operators in Ireland and the UK to show where fibre programmes lose time and money, why design quality pays back, and how we deliver networks that get built first time.

Shape the cost before it is spent

The European Commission estimates that civil engineering accounts for up to 80% of high-speed network deployment cost. While most spend occurs during construction, many decisions that determine its scale are made during design. A missed usable duct can mean new trenching; a misplaced splitter can strand fibre; unverified site conditions can trigger changes, revised packs and repeat visits. Design is the lowest-cost stage to identify and manage these risks.

Entegro designs networks that get built

Entegro has designed more than 2.8 million homes for fibre operators in Ireland and the UK. Since 2018, our team for a leading UK full-fibre operator has scaled to more than 80 designers at peak and designed just under 2 million homes. On our contract for a Tier 1 operator’s national XGS-PON overlay in Ireland, Entegro has released more than 317,000 premises for sale across overhead, underground and multi-dwelling unit (MDU) builds. Across all Entegro programmes, construction realities shape each design decision.

Where fibre programmes lose time and money

Most problems that surface during build start earlier, in the design inputs or at the handover between design and construction. Four issues recur across operator programmes.

Records that do not match the ground

Desk-based designs can rely on inventory that no longer reflects reality: blocked or full ducts, poles that fail inspection, or changed premises. On our XGS-PON overlay contract, incomplete duct and chamber records risked redesign mid-build. Our teams surveyed routes, corrected records and resolved more than 5,000 duct blockages. Identifying constraints early allows them to be assessed before construction, reducing the risk of costly crew-level intervention.

Third-party dependencies

Wayleaves, road-opening licences, access to third-party poles and ducts, and local authority standards determine what can be built and when. For a UK full-fibre operator, we gained accreditation on Openreach’s duct and pole network and verified records before design. On our XGS-PON overlay contract, our in-house team opened more than 4,000 road-opening licences with over 20 issuing authorities. These dependencies influence route, method, cost and programme, so permissions must be planned from the outset.

Complex premises

Apartment blocks, mixed-use buildings and non-standard addresses need dedicated routing, riser access and building-owner engagement. Left late, MDUs stall connection targets. Addressed early, they become volume: Entegro have surveyed, designed, wayleaved and built more than 100,000 MDU homes for our clients.

Change and drift

When site conditions differ from the design, changes can mean revised drawings, re-approval and another visit. If verified as-built changes do not flow back into the geographic information system (GIS), records can show live routes as proposed. Both reduce crew productivity and undermine confidence in the operator’s network data.

Good design pays back across the life of the network

Design quality is both a commercial and engineering issue. It influences build cost, performance, safety, operating effort and time to revenue.

Cost

Good design utilises suitable existing ducts and poles, selects buildable routes, sizes cables and controls joint counts. Our overhead designs reuse aerial routes where fit for purpose. On our XGS-PON overlay contract, Entegro has released more than 175,000 overhead premises without the trenching a new underground route would demand.

Performance

Each passive optical network (PON) is designed within the operator’s optical budget, with margin for ageing. We assess splitter configuration, route length, splice and connector losses against the operator’s specifications, and where the budget is tight we specify stubbed devices, which replace a connector pair with a lower-loss splice. Every route is tested with an optical time-domain reflectometer (OTDR) and at PON level before handover, and image-based AI checks of installed taps and closures write results straight back to the GIS.

Health and safety

Most build hazards can be designed out before a crew reaches site. We act as Project Supervisor for the Design Process (PSDP) and Project Supervisor for the Construction Stage (PSCS), and hazards are flagged online in ArcGIS at every stage, from survey to design to build, so each team sees them before it arrives. On our XGS-PON overlay contract, more than 191,000 hazard records have been logged since 2022, including potential 63,000 power conflicts recorded by cable type, which has led to 43,000 shroud requests to ESB. Designers route around high-pressure gas and high-voltage power wherever possible. Where they can’t, ESB or Gas Networks Ireland supervision are written into the job pack before work is scheduled.

Long-term maintenance

Accessible joints, consistent labelling, clear fibre allocation and verified as-builts make repairs faster and future changes simpler. Accurate data supports upgrades and service provisioning.

Speed to revenue

Build-ready packs keep crews productive and bring premises to service sooner. On a single contract, premises Entegro released for sale rose from 38,800 in 2024 to 124,600 in 2025. Design contributes alongside survey, permitting, construction and release.

How Entegro designs networks that get built first time

Our approach links survey, design, construction feedback and records in one controlled process, keeping the design, physical network and operator data aligned.

Survey and validate

We combine field survey with quality-checked infrastructure records, so designs reflect what is in the ground, not just what is on file. Where existing ducts and poles are utilised, we verify condition and capacity before release.

Design to standard, check every release

Designs follow operator rules and passive specifications. Three quality gates cover draft quality control (QC), full QC before client review and final pack QC before construction issue. An independent engineer checks each design, supported by automated rule validation.

Issue packs crews can build from

Build packs include drawings, fibre allocation, splicing schedules, work orders and patching instructions. Permits, licences and MDU requirements are tracked so crews receive work that is technically complete and ready to build.

Close the loop with build

Field queries return through controlled revisions. We track each change’s cause, turnaround and impact, then review recurring blockers with operator and build teams to remove issues at source.

Deliver the as-built record

We treat as-built records as a deliverable. For our XGS-PON overlay client, we established a GIS operating model with more than 550,000 cable records, 250,000 duct segments and 100,000 chambers, synchronised nightly with field platforms used by more than 12 contractor organisations.

Capacity to scale

Our Comsof, QGIS, PostGIS and ArcGIS Online toolchain supports design at scale: more than 80 designers for a UK full-fibre operator, 30 for a regional UK fibre operator and 20 on a national broadband programme in Ireland, where we have designed and as-built 225,000 homes since 2020. We delivered the regional operator’s 500 km backhaul network ahead of programme. Premises Entegro has released for sale on the XGS-PON overlay grew from 78,000 to 309,000 in under three years.

Key takeaways for operators

1. Validate before you design. Survey and prove infrastructure early; resolve constraints before they reach construction.
2. Agree standards up front. Define release checks and measure first-time-right performance against a clear baseline.
3. Design out hazards. Flag risks at survey and design so controls are in place before crews arrive.
4. Treat change as feedback. Categorise field changes and remove recurring causes from future releases.
5. Make as-built a deliverable. Define ownership and acceptance criteria for verified operational data.
6. Choose a partner who builds. Field experience and design assurance improve buildability.

Build it right first time

Entegro brings survey, design, quality control and build support together in one coordinated process, proven on national rollouts in Ireland and the UK. A review of your design pipeline can identify data gaps, rework, approval delays and handover issues affecting cost and time.

Talk to Entegro about improving your next fibre design programme.