TGH Tech
Case study · Bleno for construction

A signed agreement goes in. A programme, a critical path and a purchase schedule come out.

Viya Constructions is our design partner for Bleno in construction. We are taking the work that only their planner and their procurement lead can do today, writing the method down properly, and putting it into software the company owns. This is the account of what is being built, and what it is teaching us about the vertical.

Construction and engineering · Kerala, India2 workflows in buildDesign partner since August 2026Runs on Bleno
Read the account The product behind it
01 · Where it started

Three people can do the job. Everyone else waits for them.

In a construction business the decisions that make or lose the money on a project are held by a handful of people, and none of it is written down in a form anyone else can use.

One person reads the agreement and knows what the company has actually committed to. One person builds the programme and can tell you which activity is holding the completion date. One person knows that reinforcement steel takes twenty working days to land, so the order has to go out before the slab is even formed.

When those people are busy, the programme is late. When they are on site, procurement waits. When they leave, the method leaves with them.

This is not a cost problem. It is a method ownership problem, and no amount of extra software fixes it, because the software has nowhere to read the method from.

02 · Choosing the job

We looked for work that takes days, comes back every project, and only a senior person can do.

Those three tests are what make a job worth encoding. Six candidates came out of the conversations with Viya. We started with the two that feed each other.

Started here

Programme from a new agreement

Reading the scope out of a signed agreement and turning it into a dated work schedule.

Started here

Material purchase schedule

Turning that schedule and the bill of quantities into what to buy, how much, and by when.

Next

Bar bending schedule

Steel worked out from drawings, currently done by hand with a scale rule.

Next

Takeoff and pricing from drawings

Quantities and rates for a tender, where the estimator’s reasoning is the asset.

Later

Subcontractor payment run

Measured work, retention, deductions and certification, every month, for every subcontractor.

Later

Tender comparison

Several quotes with different scopes and exclusions, made comparable on one sheet.

The two we started with are connected. The programme decides when work happens. The purchase schedule cannot exist without those dates. Encoding one without the other leaves the harder half of the problem untouched.

03 · The brief

Two flows, joined at the schedule.

The whole thing is a conversion. Contract language in, planning documents out, with every line traceable back to something that was actually agreed.

FlowStarts withProduces
Flow one, programme and critical pathThe sale agreement and the scope of work it referencesAn approved work schedule, and the chain of activities that controls the completion date
Flow two, material purchase scheduleThe approved schedule and the bill of quantitiesMaterial quantities with required-on-site dates, order dates and enquiry dates

The intent behind both is traceability. Every scheduled activity should trace back to agreed scope. Every purchase should trace back to a quantity in the bill of quantities and to the date the activity that consumes it starts.

04 · Agreement to programme

Seven conversions, each with an output someone can check.

Nothing here is new to a planner. That is the point. What is new is that it exists outside one person’s head, in steps a company can run, audit and improve.

  1. Read the agreementPull out deliverables, exclusions, milestones, the completion date, approvals and acceptance conditions.Scope list
  2. Structure the scopeBreak the scope into deliverables and work packages that a person can own.Work breakdown
  3. Create activitiesTurn each package into the tasks needed to build, inspect and complete it. A ground floor slab becomes formwork, reinforcement, services inserts, inspection, pour and cure.Activity list
  4. Define the sequenceConnect activities by what genuinely has to happen before what, on this site, in this order.Schedule network
  5. Estimate durationsQuantity, production rate, crew and the working calendar. A thousand square metres of blockwork at a hundred a day is ten working days.Durations
  6. Calculate the datesRun the schedule to get early and late dates, float, milestones and a completion date to compare against the contract.Work schedule
  7. Find the critical pathIdentify the activities that control completion, and hand the result over for approval.Critical path

On standards

There is no standard that converts a sale agreement into a construction programme. Viya’s method draws on published guidance for project management and for work breakdown structures, and on the critical path method for the calculation itself, but the conversion rules in between are the company’s own.

Writing those rules down is most of the work. Until this project they existed as habit. Now they are a document, which means they can be argued with, corrected, and given to software.

05 · The critical path

The longest path through the job is the one that decides the date.

Delay an activity with float and nothing moves. Delay one on the critical path and the completion date moves with it, unless time is recovered somewhere else on the same chain.

Owners already know this instinctively. What they usually cannot get is a current answer, on a Tuesday, for a live project, without asking the one person who maintains the programme.

Early start
latest early finish of everything that must come first
Early finish
early start + duration
Late finish
earliest late start of everything that follows
Late start
late finish − duration
Total float
late start − early start
Critical
the longest valid path, normally zero float

In a real schedule the driving path can carry the lowest or a negative float rather than exactly zero, because of calendars, constraints and imposed completion dates. The software has to handle that case, not the textbook one.

06 · Buying backwards

Procurement runs in reverse, and that is where projects quietly lose weeks.

Every purchase date is calculated backwards from the day the material has to be on site. Get the arithmetic wrong once, on one long lead item, and the critical path moves. This is the piece Viya wanted most, and the piece we think travels furthest to other contractors.

Counting back from the day the activity startsRead right to left
EarliestEnquiry issuedBid period, technical and commercial evaluation, internal approval.
thenOrder placedAfter the quotes are compared and the make is approved.
thenMade and inspectedManufacture, fabrication and any required inspection.
thenDispatchedTransport time to the site, with a procurement buffer held.
thenRequired on siteAllowing days for receiving, checking and handling.
FixedActivity startsSet by the programme. Everything else is calculated from here.
CalculatedGiven

Change the programme and every date on this line moves. That is why the purchase schedule is generated from the schedule rather than kept beside it.

Quantity is not the bill of quantities

The bill gives the measured quantity. What you buy is a different number once wastage, usable stock, client supplied material and delivery packaging are taken into account. Getting that wrong ties up cash or stops the pour.

Bill of quantities, reinforcement steel100 t
Approved wastage at 3 per cent103 t
Usable stock on site−8 t
Purchase quantity95 t
Activity start on the programme30 Nov
Required on site, after handling26 Nov
Order deadline, 20 working days earlieron the project calendar

Illustrative figures from the workflow document, not a live project.

The five conversions

  1. Link the bill to the activitiesEvery material line mapped to the work package that consumes it.Mapping
  2. Spread it over timeQuantities split by floor, zone and the period the work is planned in.Demand by date
  3. Set the site dateWhen the material has to be there, allowing for receiving and handling.On-site date
  4. Apply the lead timeWork back through delivery, manufacture, inspection, approval and enquiry.Order and enquiry dates
  5. Issue the scheduleMaterial, specification, quantity, the activity it feeds, supplier and every date.Purchase schedule
07 · What Bleno holds

The tool is the small part. The method is the thing being bought.

Bleno holds how this company does each job, so what comes back needs a read rather than a rewrite. In construction that means three specific things.

Context

Viya’s own rules

The conversion rules from agreement to scope, the standard activity breakdowns, approved wastage percentages, approved makes, supplier lead times, production rates and the working calendar.

Utilities

Named jobs, not a blank box

A person opens “build the programme from this agreement” or “produce the purchase schedule for this floor” instead of describing what they want to a chat window.

Costs

A ceiling the owner sets

Routine extraction runs on cheap models, hard reasoning runs on the best one, every call tied to the job and the person who triggered it, inside a monthly limit.

Viya approve a proposed harness rather than authoring one. A construction firm has nobody whose job is populating an AI platform, and pretending otherwise is how these projects stall in month two.

08 · Two modes

Someone has to notice. On most sites, nobody is watching between meetings.

A workflow waits to be opened. An agent watches and speaks first. Both matter, and the second one is what construction is short of.

User triggered

Workflows increase execution capacity

A person picks a known job and Bleno helps produce the expected output. The programme, the purchase schedule, the schedule of steel. Useful the moment it exists, and it only runs when someone asks.

Event triggered

Agents increase organisational attention

Data, a date or a threshold starts the work instead of a person. An order date arrives with nothing raised against it. A critical activity slips. Bleno surfaces what now needs a decision, with the evidence attached.

  1. 01Authorised dataReads only the systems it has been permitted: schedule, bill of quantities, orders, site records.
  2. 02AnalyseChanges, patterns, history and how one record relates to another.
  3. 03Find significanceThresholds, deadlines, context and risk. Most changes matter to nobody.
  4. 04Direct attentionAlert the named owner, explain it, and show the evidence behind it.
  5. 05MobiliseRecommend, prepare the response, or start an authorised workflow.
09 · Agents for a site

Four things worth watching on a live project.

Scoped with Viya against real problems from real projects. None of these are deployed yet. They are here because they are what the two workflows make possible once the data exists in one place.

01

Order deadline agent

Procurement
Watches

The purchase schedule, enquiry and order dates, supplier confirmations, approved makes and any change to the programme.

Detects

An order date approaching with nothing raised, or a schedule change that pulls a delivery date earlier than the lead time allows.

Alert

The item, the activity waiting on it, days remaining, and the buyer responsible.

02

Critical path agent

Programme
Watches

Progress against planned dates, float on the driving path, and activities that have just become critical.

Detects

A critical activity slipping, or float falling far enough on another chain that it is about to take over as the one controlling the date.

Alert

What moved, what it does to the completion date, and which recovery options exist on the same chain.

03

Scope and variation agent

Commercial
Watches

Site instructions, drawing revisions and daily records against the scope the agreement actually commits to.

Detects

Work being carried out beyond agreed scope with no approved variation behind it.

Alert

The instruction, the scope line it exceeds, and the approval that is missing before the cost lands.

04

Billing readiness agent

Cash
Watches

Completed activities, measurements, client acknowledgements, purchase orders and what has already been certified.

Detects

Work finished and not yet billed, and which piece of evidence is holding each one up.

Alert

What can be billed today, what is blocked, and the one action that unblocks it.

10 · Bounded agency

An agent is only useful if you can say exactly what it may do.

Nobody is going to let software touch a live programme or a purchase order on trust. Six limits are set before anything is switched on.

Authorised sources

It reaches only the systems and records explicitly permitted for its job, and nothing else.

Defined conditions

Thresholds, deadlines and exceptions are written down and can be changed by the company.

Named ownership

Every alert goes to a person or a role, with an escalation path if it sits unread.

Traceable evidence

It shows the records and the reasoning behind what it raised. No unexplained conclusions.

Permissioned action

It may observe, recommend, prepare or act only within the authority it has been given.

Human control

Anything commercial, contractual or safety related stays approval bound, by default.

11 · The partnership

Built with one contractor, not for an imagined one.

Viya is a design partner rather than a customer buying a finished thing. Bleno for construction is being shaped inside their actual week, on projects they are actually running.

What Viya givesWhat Viya gets
A workflow the business genuinely depends on, not a sandboxThe product shaped around how their work is really done
A named owner with the authority to make calls, an hour a fortnightTheir problems prioritised ahead of speculative roadmap work
Frank reactions on the day, not a summary at the quarterPartner terms that hold for the life of the relationship
Permission to write the method down and argue about itThe configuration and standards stay theirs either way
12 · Where it stands

Said plainly, because a case study that only reports wins is not worth reading.

The method, written down

Both flows documented end to end, including the conversion rules, the formulas and the fields each output must carry. Reviewed with Viya and revised.

Done
Flow one, agreement to programme

In build against the documented method. The hard part is the conversion from contract language to work packages, which is judgement before it is software.

In build
Flow two, purchase schedule

Depends on flow one producing an approved schedule. The backward date calculation and the quantity rules are specified.

Next
The four agents

Scoped with Viya, not deployed. They need the schedule and the purchase schedule to exist as data first.

Scoped
Time saved

Not claimed yet. We are measuring the current effort on the programme and the purchase schedule for the first two projects, and the same effort afterwards. The numbers go here when they exist.

Measuring

One thing we already got wrong. The first version of the method treated the bill of quantities as the purchase quantity. It is not, and a contractor spots that in about four seconds. The rules for wastage, usable stock and client supplied material came directly from Viya correcting us.

13 · What transfers

The rules are Viya’s. The shape of the job is everyone’s.

Every contractor has its own wastage percentages, its own approved suppliers, its own sequence for a slab. None of that copies across, and it should not.

What does copy across is the shape. A signed agreement that has to become a dated programme. A programme that has to become a buying plan. A completion date controlled by a chain of activities that nobody can name on demand. Those are the same jobs in every construction business of this size, done by two or three people who are always busy.

Bleno holds the method, whoever’s method it is.

The work with Viya is what taught us which jobs to start with, and how much of the method has to be written down before software is any use at all.

Name the job that only two people in your company can do.

If it takes days, comes back every project, and stops when those two are on site, that is the conversation. We will tell you honestly whether it is a good first one.

Start a straight conversation See how Bleno works