So what is involved in getting the pool floor looking great again:
There is a need to understand the depth of the pool floor and whether metal reinforcement grids were used in the initial build.
A 20cm hole needs to be made. The method proposed is to drill several holes down 10cm remove remaining masonry and check for reinforcement grid sighting. If no sighting, then drill down a further 10cm and re-inspect. With no sighting drilling will be carried out in 5cm steps until a 30cm deep hole has been created.
Should there be no grid reinforcement sighted, drilling may subsequently break through to the substrate under the pool floor. The level of risk to the pool structure due to the bore hole and the possible breakthrough to the substrate below is deemed ‘Low’.
The fissure, i.e. crack across the pool, is not the problem. The risk to the pool structure is once the screed has been laid without knowing whether a reinforcement grid was employed or not. The fissure might therefore act as a cantilever fulcrum and thus with the increase in weight due to the screed, cause the floor of the pool to press down on the substrate below. The result of which may cause the pool floor to break away from the walls.
It is difficult to calculate at this time the net effect of the cantilever force and the constraint that may be provided by the screed itself given that the depth of the pool floor is presently unknown.
Thus, ensuring the fissure is reinforced by adding in a reinforcement grid, to assist the reinforcement grid already in situ or not, should, reduce the force effect on the pool floor at the deep end. The level of risk to the pool structure for inserting a supporting reinforcement grid is deemed ‘Low’.
The are several conditions to be met before the screed can be laid, and are:
a. Floor has been scabbled and cleaned,
b. Expansion Band set in place and
c. Bonding slurry has been applied.
Items a. and c. above will have a detrimental effect for the screed. Thus, without due diligence the screed will not be bonded effectively and thus will be less effective.
Equally, should the bonding be inadequate, for whatever reason (incorrect screed mix including additives, etc), there is a possibly that it may crack in places of weakness. This may also occur if the screed is not left to dry out. No option has been considered to lay the screed in sections as it is unlikely that the necessary work force would be available. Also, the screed floor would have to have expansion joints inserted between screed sections.
Further, the smoothness of the finished surface must also be taken into consideration given the area of coverage.
As the screed is to be produced in-house by HSC members and laid in one day, this a considerable task. Thus, the level of risk, at this time of writing the report, is deemed ‘High’.
Painting of the Pool:
Re-painting the pool will give the floor secondary skin to protect the screed against damage and aging. How it is painted will govern the level of risk. Should painting the pool follow what has been defined then the risk is deemed to be ‘Low’.
A summary of how long each task is likely to take and the number of people required to do this task is detailed in the table below:
|Task Description||Task Duration||Team Size|
|Exploratory Bore Hole||2 Days||2/3|
|Fissure Renovation||4 days||3/4|
|Pre-Screed Production||1/2 days||6/8|
|Screed Production Part I||1 day||4|
|Screed Production Part II||1 day||8|
|Pool Painting||1 + 1 day||3/4|
For a full thorough copy of the report completed by David Morgan, please click link below to view:
Our thanks goes to David Morgan for producing such a thorough and detailed report.