What is an internal rainwater pipe system and how does it work?

An internal rainwater pipe system plays a crucial role in managing and directing rainwater within buildings.

Whether for residential, commercial, or industrial structures, this system ensures that rainwater is safely collected and channelled from the roof and other surfaces to designated drainage or storage systems.

Because internal rainwater pipes are hidden away from public view, many of us go through life blissfully unaware of such systems. Out of sight, out of mind and all that.

The time has come through for PipeRepair.co.uk to sing the praises of these important, unseen drainage systems by explaining what they are, how they work and the benefits they offer.

What is an internal rainwater pipe system?

An internal rainwater pipe system is a network of pipes installed within a building’s structure, designed to transport rainwater from the roof or other exposed areas to the ground or a water storage system.

Unlike external systems, which are visible on the exterior of a building, internal systems are hidden within walls or ceilings, making them less susceptible to environmental damage.

This makes them particularly popular drainage systems for skyscrapers, office blocks, large public facilities like hospitals and other public buildings where running hundreds of metres of exterior guttering is impractical.

Components of an internal rainwater pipe system

There are five core components in an internal rainwater pipe system. Some are similar to what you will find in general guttering. Others are specialist parts required because of the complexity and size of internal drainage.

Gutters and downspouts

Whilst gutters and downspouts are key components of external rainwater drainage systems, they are also found in internal systems – normally at the point on a building’s roof where rainwater is collected. From there, gutters and downspouts channel water into downpipes.

An internal rainwater pipe system will also include downspouts inside the building to direct water through.

Rainwater pipes

The core of an internal rainwater pipe system, rainwater pipes are typically made from materials such as PVC, cast iron, or copper.

These pipes transport rainwater from the roof or external areas to the internal drainage system. They are installed vertically through the structure, from roof to basement or ground level.

Seals and flanges

Seals and flanges are used to prevent leaks at connection points and ensure that water flows efficiently through the system. These are crucial for maintaining the integrity of the internal system and avoiding water damage.

Drains and manholes

Rainwater collected in internal pipes is often directed into drains or large underground holding tanks. These drains may connect to a building’s main drainage system, a stormwater system, or even a rainwater harvesting tank.

Many new skyscrapers and other public buildings are being constructed with rainwater harvesting tanks for sustainability and the ultimate goal of achieving net-zero water use.

Vents

Ventilation openings, sometimes integrated into the pipe system, help regulate pressure and allow air to escape as the water moves through the system.

Vents prevent blockages and help ensure that the system operates smoothly. With internal pipe systems often running through cavity walls or between the floors, the last thing anyone wants is to start dismantling parts of a building to reach and release a blockage.

How does an internal rainwater pipe system work?

The internal rainwater system begins with the collection of rainwater from the roof. Water flows along the roof’s surface, where it is captured by internal gutters or channels that lead to downpipes.

These downpipes funnel the water into vertical pipes within the building, which then transport it to the ground level.

Once at ground level, the water may enter the building’s main drainage system or be directed towards a storage solution.

In buildings with multiple floors, internal rainwater pipes are typically installed in walls or cavities, running vertically to avoid obstructing the living space.

The pipes are designed to ensure that rainwater flows without causing blockages or leaks. Once the water reaches the ground level, it is typically channelled into either a storm drain system or a rainwater harvesting tank for later use.

Benefits of an internal rainwater pipe system

Internal rainwater pipe systems are more expensive to install than traditional guttering. But they offer a number of benefits which far outweigh the costs for many developers.

Aesthetic appeal

Since internal rainwater pipes are concealed within walls or ceilings, they do not interfere with the building’s exterior appearance.

This helps preserve the aesthetic integrity of the building, especially where external pipes may be considered unsightly.

Protection from weather conditions:

Internal rainwater pipes are less vulnerable to the elements compared to external systems. They are protected from the wear and tear caused by temperature fluctuations, physical damage or corrosion which might impact external pipes.

Improved safety

An internal system can be more secure and less prone to damage from accidents, vandalism, or extreme weather events.

Additionally, internal pipes are usually not as susceptible to clogging from debris that might enter external pipes.

Durability and Maintenance

Because internal systems are sheltered, they tend to last longer. This means they require less maintenance than external systems and makes internal rainwater pipe system repair rare.

Also, internal rainwater pipes are often designed with better protection against wear, giving them a longer lifespan.

Rainwater harvesting

Internal systems can be integrated with rainwater harvesting systems. This allows water to be collected and stored for reuse in irrigation, flushing toilets or even for potable use in some cases.

Recycling rainwater helps conserve natural sources, reduces water bills and contributes towards protecting the environment.

Reduced risk of water damage

Properly installed and maintained internal rainwater pipe systems ensure that water is directed away from vulnerable areas, such as basements or crawl spaces. This reduces the risk of water damage to the building’s foundation, walls and flooring.

The popularity of internal rainwater pipe systems

An internal rainwater pipe system is a vital part of any building’s plumbing infrastructure. It efficiently collects and channels rainwater away from the structure, protecting it from water damage and ensuring that water is directed toward appropriate drainage or storage solutions.

Whether you are building a new home, renovating an existing one or managing a commercial property, understanding and maintaining your internal rainwater pipe system can help preserve the integrity of your building whilst promoting sustainable water use.