1. Why renovation is harder to estimate
Three structural reasons, and the third is decisive for apartment buildings. It concerns the actual condition of the building.
The initial situation is not fully known, unlike new construction where everything has been designed. The work is carried out on the terms of the existing structure rather than in ideal conditions. And the building is usually in use, which limits the organisation and lengthens the time, as covered by the article on living in the building during works.
The first two mean that part of the cost only emerges as the work proceeds, as covered by the article on unforeseen circumstances. A contingency has to be built into the budget.
2. What affects the cost
Four factors of different character, and the fourth is the most often left out of the discussion. It concerns later running costs.
| Factor | What it determines |
|---|---|
| The building's present condition | how much preparatory work is needed |
| The required class gain | the volume of work |
| The shape and size of the building | on a smaller building the fixed costs spread over less area |
| The organisation and duration of construction | site costs |
The fourth is dealt with separately by the standard on the classification of construction costs and is explained in the budgeting guide: site-related costs depend on the organisation and the duration rather than on the design solution. Shortening or lengthening the programme therefore changes the cost even where the works are the same.
3. Why a rate per square metre misleads
Three reasons apply more strongly in renovation than in new construction, and the third is decisive in support terms. It concerns residents being in occupation.
The same rate per square metre may cover very different volumes of work, depending on the initial condition. A rate per square metre does not include unforeseen circumstances, which are the rule in renovation. And a rate per square metre does not say what class gain it achieves.
A cheaper rate per square metre that does not reach the required class is not cheaper but useless. Orders of magnitude for construction cost and price indices are covered in a separate guide, which also explains why the Estonian renovation index does not cover residential buildings. This guide states no rates per square metre, because they depend on the initial condition more than on anything else.
4. What to allow for in the programme
Four stages, of which only one is construction. The other three together last longer.
| Stage | Note |
|---|---|
| Preparation and decision | covered in a separate branch |
| Application and funding decision | the duration depends on the round |
| Procurement and contracts | |
| Construction and final measurements | the measurement protocols must be planned into the programme |
The required measurement protocols are covered by the article on the full package. Seasonality is a separate factor in Estonia, since facade works are not carried out in winter on the same terms, and this affects both the programme and the price.
Summary and four practical rules
Renovation is harder to forecast for three structural reasons: the initial situation is not fully known, the work is done on the terms of the existing structure, and the building is usually in use. Four factors affect the cost, of which the organisation and duration of construction are the most often left out of the discussion, even though changing the programme changes the price for the same works. A rate per square metre misleads because it does not say what class gain it achieves, and a cheap solution that does not cross the threshold is useless.
Four rules: do not judge a renovation by its rate per square metre. Ask what class gain the price achieves, not only what the price is. Allow for the effect of the programme on the cost, not only the volume of works. Plan the final measurements and seasonality into the programme from the start.
This article offers professional orientation as at the date of verification. It is not a quotation.