what happens when your bathroom floor doesn’t have sufficient slope?

Nemmadi.in Home Inspection Slope

What do we mean by “slope“?

Slope of a surface means the surface of which one end or side is at a higher level than another, a rising or falling surface.

The dictionary definition of slope

It is the ratio of the vertical rise to the horizontal distance followed on the ground for that vertical rise.

It is of two types.

  • Longitudinal slope.
  • Cross slope.

In an Apartment or Villa there are various floor surfaces that require slope, each surface needs a different slope which reflects the use of the slope

  • Toilets – Wet & Dry areas
  • Utilities & Balconies
  • Terrace
  • Basement & Car parking areas
  • Roads
  • Drains & Plumbing lines

Improper slope in bathroom – drains money instead of water

If slope is not provided in proper direction , then floor water will drain easily as it will flow a direction opposite to floor drain outlet/grating. It will lead to water pockets at corners and lead to damp / seepage related issues in adjacent wall or floor surface.

This will lead to damaged property / associated furniture and health issues. Moreover its  rectification  will cost large amount and time factor.

This will lead to damaged property / associated furniture and health issues. Moreover its  rectification  will cost large amount and time factor.

Carom pocket earns points, water pocket drains money

Inadequate slope at flooring can lead to formation of water pockets, hence floor water will not get drained easily from floor drain outlet and get accumulated at the corner. It will lead to damp/ moisture seepage related issues in adjacent areas, and also water seepage in the below floors.

Nemmadi.in Home Inspection Slope Issue

This can cause damage to property/ associated area and health issues in long run. Moreover its rectification will cost large amount and time factor.

  • The slope requirement is decided on two factors

Nemmadi.in Home Inspection Slope Issue

  • The below table shows slope requirements based on the factors shown in the table earlier

Nemmadi.in Home Inspection Slope Issue

The slope may be mentioned in two ways,

  • as a ratio (ex: 1:100 or 1 in 100)
  • as a percentage (ex: 1%)

The above table gives the slope requirement for assumed floor finish, In case of change in floor finish, slope has to be decided suitably.


  • Toilet wet area is – Shower area
  • Toilet dry area is – EWC & Hand wash area.

No compromise with the slope

Water must run off and not be allowed to accumulate on the top covering or substructure in order to avoid hydro static pressure.

Balconies and terraces must be planned with a minimum slope of 2 %, however, if the slope exceeds 3 % , the slant may cause negative effects for the use of the balcony or terrace. If ceramic tiles or natural stone slabs are embedded in mortar , it is also necessary for the top layer ( wearing surface ) to have adequate slope. This ensures proper drainage of the water.  An exception : loose – layered structure with a built-in drainage system that allows the water to run off underneath the top layer.

Improper slope in toilet, balcony, utility, terrace, etc will lead to…

  • Damp / seepage related issues in adjacent wall or floor surface
  • Fungus issue on floor surfaces
  • Flooring & wall surface strength decreased
  • Unhealthy conditions in house
  • Safety hazard

Improper slope for window’s chajja & sill  

This will causes seepage & surface deterioration, because of a reverse slope towards window, external rain water will not drain easily and water will penetrate inside house through frame and sill junction.  This will lead to paint deterioration and other damages internal wall surface around window in long run.

Direct Solutions

We recommend a review and if required, floor tiles to be relaid maintaining proper slope towards floor drain outlet and adequate strengthening of sealant at floor and wall tile junction.

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