1. What changes when the building is occupied
Four constraints all lengthen the work, and the second has the greatest effect on time. It concerns restrictions on working hours.
| Constraint | Content |
|---|---|
| Working hours are limited | noise is not permitted at night or early in the morning |
| Access to apartments has to be agreed | coordination with each apartment separately |
| Heating and water must work | or be temporarily replaced |
| Safety is stricter | children and elderly people move about the site |
If one apartment is not accessible at the agreed time, work on the whole riser stops. The organisation of access must therefore be planned and communicated before the works begin rather than resolved as they go.
2. Four questions of organisation
These must be decided before the procurement, because they affect the tenders. A constraint added later carries a price.
Whether the work proceeds riser by riser or floor by floor. How temporary heating is arranged while the heating system is switched off. Where materials are stored and how access is organised. And how damage inside apartments is dealt with where it occurs.
The fourth is the most often left open and causes the most conflict. The procedure has to be agreed beforehand, because agreement is harder at the moment damage occurs.
3. What it does to the cost
Three mechanisms, and their conclusion is counter-intuitive. The faster route is not always the cheaper one.
The working time lengthens, which increases site costs. Temporary arrangements cost money, including heating, covering and access routes. And phased work is slower than work done all at once, because the team moves back and forth.
The dependence of site costs on duration is covered in a separate guide on budgeting, and it is directly relevant for an occupied building. A solution that shortens the time spent on site may therefore be cheaper overall even at a higher unit price, and prefabricated elements are an example of that logic, as covered by the article on the support rate.
4. How to prepare the residents
Four steps reduce conflict more than any technical solution, and the fourth is preventive. It concerns the rhythm of communication.
Explain the programme before the start, including what happens when. Name a single contact person to approach. Warn in advance about the noisiest stages. And explain why ventilation is necessary before it is installed.
A ventilation unit in an apartment provokes resistance where its purpose has not been explained, as covered by the article on the full package. A resident who understands why the work is being done tolerates the disruption considerably better than one who was given only a date.
5. What to write into the contract
Four points, all of which affect the tender price. The limits on working hours and the procedure for the noisiest works. The organisation of access and the notice period. The arrangement for temporary heating and water. And the procedure for dealing with damage.
All four must be in the tender documents rather than agreed after the contract is signed, because after the contract there is no longer any competition to bear on the price. The position is weaker afterwards.
Summary and four practical rules
An occupied building imposes four constraints, of which access has the greatest effect on time, since an inaccessible apartment stops work on the whole riser. Four questions of organisation must be decided before the procurement because they affect the tenders, and the procedure for dealing with damage is the most often left open and causes the most conflict. Longer working time and temporary arrangements increase site costs, so a solution that shortens time on site may be cheaper even at a higher unit price.
Four rules: decide the organisation of the works before the procurement, since it affects the price. Plan access rather than resolving it as you go. Consider solutions that shorten time on site, even at a higher unit price. Explain the purpose to residents, not only the programme.
This article offers professional orientation as at the date of verification. It is not a quotation.