How to Install a Downstairs Toilet: A Step-by-Step Guide

Adding a downstairs toilet to your home can be an incredibly practical and valuable improvement. Whether you have a growing family or entertain guests frequently, a downstairs loo can offer convenience and boost the value of your property. Installing a downstairs toilet is a considerable DIY project, but with the right preparation and guidance, it’s achievable. This blog post will cover everything you need to know about how to install a downstairs toilet, including the best position, materials required, planning considerations, soil pipes, and the pros and cons of this home improvement.

Planning Your Downstairs Toilet Installation

Before diving into the installation process, the first step is careful planning. When deciding where to install your downstairs toilet, you need to take into account the space available, the proximity to existing plumbing, and the flow of your home. Ideally, it should be positioned close to the existing soil stack to minimise the need for extensive plumbing work. If your home does not already have a soil stack, you will need to plan for one, which may involve some extra cost and work.

It’s also essential to consider local regulations. In the UK, you’ll likely need to comply with building codes and obtain permission if necessary. While minor internal plumbing adjustments don’t always require planning permission, it’s still a good idea to check with your local council to be sure.

Best Position for a Downstairs Toilet

The best position for your new downstairs toilet depends on several factors:

1. Proximity to Existing Plumbing: The closer the new toilet is to your current plumbing, especially the soil stack, the easier and cheaper the installation will be. If the new loo is far from the existing pipes, you may need to add extra piping, which could be costly.
2. Space Availability: It’s crucial to ensure there’s enough space for both the toilet and the surrounding fixtures. The smallest bathroom space is typically around 1.5m x 1.5m, though a larger room offers more comfort and flexibility.
3. Ventilation and Lighting: You should also ensure the toilet is well-ventilated, especially if it’s placed in an area with no windows. A fan is typically required for ventilation, and adequate lighting is a must for both comfort and safety.
4. Privacy: Ideally, the toilet should be located in a private area, away from high-traffic zones. You may want to place it near a hallway or tucked under a staircase for easy access.

Materials Required for a Downstairs Toilet Installation

Installing a downstairs toilet requires a variety of materials. Here’s a list of essential materials you will need for the installation:

• Toilet Bowl and Cistern: You can choose from wall-hung or floor-mounted toilets. Wall-hung toilets provide a modern, sleek look and save space, while floor-mounted toilets are more traditional and easier to install.
• Soil Pipe: This is the pipe that carries waste from the toilet to the main drain. A 110mm PVC soil pipe is standard in most UK homes.
• Water Supply Pipes: You’ll need a water supply pipe to connect the toilet cistern to your home’s existing water system. Typically, a 15mm pipe will suffice.
• Saniflo Pump: If your downstairs toilet is far from the soil stack or located in a basement, you might need a macerator or Saniflo pump. This device helps pump waste through smaller pipes, making it possible to install a toilet in locations where gravity drainage isn’t an option.
• Sink: If you plan on installing a sink with your downstairs toilet, you’ll need an appropriate basin, tap, and associated plumbing fixtures.
• Waste Trap: For the sink, a waste trap is needed to prevent any foul smells from entering the room.
• Sealant: To prevent leaks, use high-quality sealant around joints and pipe connections.

Installing a Downstairs Toilet

Step 1: Mark the Position of the Toilet

The first task in the installation process is to decide where to position your toilet and sink. Use a tape measure to ensure there’s enough space for all fixtures and mark the positions of where the toilet and sink will sit. Ensure the toilet is installed with sufficient clearance from the walls and other objects (typically at least 300mm from the side walls).

Step 2: Install the Soil Pipe

Next, you’ll need to install the soil pipe, which should run from the toilet to the main drain. If you’re using a Saniflo pump, this process is simplified as the pump will take care of waste movement, but you’ll still need to install an outlet pipe to connect to the waste system.

For standard installations, connect the soil pipe to the toilet outlet, and ensure that the pipe runs at a slight downward angle (around 1:40) to allow waste to flow away with gravity. Secure the pipe in place with brackets.

Step 3: Install the Water Supply Pipe

To provide water to the toilet cistern, install a water supply pipe that will connect to the nearest cold water pipe in your home. This step may require cutting into your existing plumbing, so ensure you know how to shut off the water supply before beginning.

You can use compression fittings to connect the water supply pipe to the cistern’s inlet valve. Once everything is in place, check the system for leaks by turning the water back on.

Step 4: Install the Toilet and Sink

Once the plumbing is in place, you can now install the toilet and sink. Begin by fitting the toilet to the floor using the appropriate screws and securing it to the soil pipe. If you’re installing a wall-hung toilet, you’ll need a frame system to support the toilet bowl.

Next, install the sink and connect it to the waste trap and water supply pipes. Use a spirit level to ensure everything is aligned properly and securely tightened.

Step 5: Finishing Touches

Once all plumbing and fixtures are in place, apply sealant around the base of the toilet and sink to prevent any water from leaking. You may also want to add wall tiles or waterproof paint to protect the walls and ensure long-term durability.

Step 6: Test the System

Finally, test the entire system by flushing the toilet and running water through the sink. Check for leaks and ensure everything is functioning properly. If there are any issues, turn off the water supply and fix any problematic areas.

Pros and Cons of Installing a Downstairs Toilet

Like any home improvement, installing a downstairs toilet comes with its advantages and challenges. Here’s a breakdown of the pros and cons:

Pros

1. Increased Convenience: A downstairs toilet can save you time and effort, especially when you have guests or family members frequently using the bathroom.
2. Added Value: Having an additional toilet can increase the value of your home, which can be beneficial if you plan to sell in the future.
3. Space Utilization: A downstairs toilet makes use of otherwise wasted space, such as an under-stairs cupboard or small hallway.
4. Improved Functionality: A downstairs loo is useful in homes with multiple storeys, preventing the need to go upstairs to use the toilet.

Cons

1. Installation Costs: The cost of installing a downstairs toilet, especially if plumbing needs to be rerouted, can be significant. If you need a Saniflo pump, this adds to the cost.
2. Space Limitations: Depending on where you install the toilet, space might be tight. Finding a suitable position that allows for comfort and privacy may be challenging.
3. Ongoing Maintenance: Like any plumbing system, a downstairs toilet requires maintenance. Leaks, blockages, and general wear and tear may need to be addressed over time.

Installing a downstairs toilet is a practical and beneficial home improvement project that can provide extra convenience for your household. By following the necessary steps, planning carefully, and choosing the right materials, you can successfully install a downstairs toilet that will serve you for years. Learning how to install a downstairs toilet gives you some options. Whether you choose to tackle the project yourself or hire a professional, it’s important to plan the installation carefully and consider the costs, benefits, and potential challenges before you begin.

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