Why you need a drainage plan for your new home

Having a drainage plan for your new home from the onset can save you a lot of strife in the long-term.

Unless you are an expert in the matter the word ‘’drainage’’ probably doesn’t pique your interest all that much. However with all this rain we are experiencing across the ACT at the moment it’s likely something that crosses your mind more than you’d care to admit. Drainage is probably not one of the first things you’d think about when designing your dream home. However it is one of the most important things. Properly designed and implemented drainage is what is going to protect your home and property from flooding and water damage. Here at Homes by Howe we’ve compiled the ultimate beginners guide to get you up and running. A basic understanding of this fundamental aspect of construction means you’ll be able to ask your builder the right questions when it matters most.

What is drainage?

Drainage is the natural or artificial means of intercepting and transporting stormwater runoff. There are numerous components to drainage. It is usually constructed as a system placed around residential buildings to remove excess water from the area.

How does it work?

Drains remove excess water and redirect it to a central reservoir or approved catchment area. They allow water to flow elsewhere so as not to cause damage to property.

Why do I need to think about drainage?

Drainage is a critical part of building design. A good drainage system is important to prevent flooding as well as mould and structural damage to your property. Water can cause a lot of problems if you don’t plan for it. Rapid changes in weather conditions are becoming the norm. The frequency of freak storm events accompanied by unprecedented levels of precipitation is rising. It is more important than ever to have a robust drainage system that is equipped for sporadic changes in climate.

What are the benefits of having a proper drainage system?

A proper drainage system prevents water from accumulating around your home, potentially causing damage to its structure or foundations. Instead excess water is redirected and drains away from the site. A proper system reduces the chance of soil erosion, preventing mud and topsoil from washing away. This maintains a healthy water balance on your property, which can be affected during construction works and structural interventions. Proper drainage is also essential for ensuring peoples health as it safely removes waste water.

Why should I have a drainage plan before I begin construction?

Having a drainage plan from the onset of your build ensures that no mistakes are made. It can help to avoid issues from arising in the future and in other areas of the construction of your knock down rebuild. Having a drainage plan makes sure that construction of your new home is seamless by helping other tradespeople onsite identify the location of the system.

What are the different options?

There are number of different drainage options. The best option for one property may not be the best for another. Here is a quick summary of some of the most common systems:

Trench drains: Trench drains are a surface drainage system. They are a series of trenches and grates that move water towards an underground pipe. This pipe directs the water to an outlet or other accepted runoff areas. Trench drains prevent flooding and pooling from occurring and often have a slight slope so that water can easily enter them. 

Subsurface drainage systems: these are used to make sure that water does not build up in the soil substrate surrounding your house. They consist of a main drain that is fed by a series of ditches and underground pipes. Installing them requires groundwork to be undertaken.

Slope drainage systems: A slope drainage system prevents the build up of groundwater. Directing it away from your home through a series of inclined pipes. The angle ensures that water enters the drains and doesn’t pool. If you want to know more about building on a sloping block check out our other article ‘’Things you need to know before buying sloping land’’.

French drains: French drainage systems are usually used in residential projects to redirect water away from landscaping and homes. They consist of a series of pipes that move water runoff away from property and towards grey water systems, swales or cisterns.

As with all things it is best to talk to a range of experts from your builder, plumber and even a stormwater engineer if you are constructing in a heavy flow or flood prone area.

How do I know which is best option for my property?

To get a full picture of the drainage conditions on a property you need to understand how it interacts with its surrounding landscape. Property drainage systems often work in partnership with the adjacent road or urban drainage system. The best way to find out which drainage or combination of drainage options is best for your property is to talk to your builder. From there they may direct you to a stormwater professional if they feel it is needed.

What is the difference between drainage problems and flooding problems?

A drainage problem is very different to a flooding problem. Drainage problems are often linked to building and landscaping issues. This can be due to building activities that interfere with groundwater flows or overland flows passing through a property. Essentially any structure that interferes with the normal passage of stormwater has the potential to cause drainage issues.

How will I know if my land or property is prone to drainage issues?

There are a number of things you can do to assess your blocks drainage. These are:

• Note the position of your property in relation to the local topography. Things of note include placement of hills and valleys. Valleys form the primary flow path for concentrated stormwater run-off.
• The position of your house on the property. Is it positioned in a way that allows excess water to run-off or flow safely around the building?
• Is the land surrounding your home contoured to direct stormwater runoff around the building?
• Look at the flood maps for your local area. However it is pertinent to note that local drainage problems can cause stormwater-flooding issues well outside of mapped areas. This is where consulting an engineer specialising in drainage can be advantageous. They can interpret government supplied flood data and undertake site specific modelling for you.
• Some flood maps will also identify overland flow paths. These tend to only cause property damage when blocked or obstructed.

How do I get a drainage plan?

If you think you may have major drainage issues then it would be best to consult a drainage engineer or expert. If they are not major then you builder or plumber will be equipped to advise you. A knock down rebuild specialist like Homes by Howe will be able to help you draw up a drainage plan for your new home.

Hopefully this has helped you to get your head around the basics of residential drainage. As with all things it is best to consult an expert if you are unsure about something. Get in contact with Home by Howe today to make your dream home a reality!

Sources

Witherridge, Grant. ‘’A Public Guide to Managing Stormwater Drainage on Residential Properties’’. Brisbane: Catchments and Creeks Pty Ltd, (2020).