How to Deal with Manholes and Drains When Building a Patio
You've designed the perfect porcelain patio.
Then you notice it.
A manhole cover right in the middle of it.
It's an incredibly common problem in garden landscaping. Drainage pipes, inspection chambers and manholes often run directly through the area where homeowners want their new patio.
Traditionally, the solution has usually been to incorporate the access cover into the finished paving.
At Garden Ezee, we can often approach the problem differently.
Because we install patios using the iGarden iFrame system, we're able to build the patio structure above existing drainage while retaining access underneath.
That means the drain can remain a drain – without necessarily becoming the main feature of your new patio.
Why Can't You Just Cover a Manhole?
Manholes and inspection chambers exist for a reason.
If there's ever a blockage, damaged pipe or drainage problem, someone needs to be able to get back into them.
Simply constructing a conventional patio permanently over a manhole isn't an appropriate solution.
Traditionally, this means bringing the access point through to the finished patio level.
A recessed cover can then be installed and paving cut to fit inside it.
Done well, this can look reasonably neat.
But it's still there.
And if your manhole happens to sit directly in the middle of a beautifully designed porcelain patio, it's not always the finish you'd choose.
Garden Ezee's Approach: Build Above It
This is where the iGarden iFrame system gives us another option.
Instead of constructing a solid patio directly onto the ground, we create a free-standing galvanised steel framework above it.
Before installing the frame, we identify the position of all drainage, manholes and other services.
The frame layout can then be planned around those areas.
The existing manhole remains underneath.
The steel structure spans around it.
And the porcelain patio is installed above.
From the garden, you see a continuous porcelain surface.
But underneath, the drainage infrastructure remains accessible.
How Do You Get Back to the Manhole?
This is the clever part.
The porcelain on an iFrame patio isn't permanently bonded onto a mortar bed.
It's dry laid onto specialist supporting pads.
Individual porcelain tiles can therefore be lifted using suitable suction lifting equipment.
Where there's an important access point underneath, we record its location as part of the installation.
If the drain ever needs attention, the appropriate porcelain tile or tiles can be lifted.
The drainage engineer can gain access to the chamber.
Once the work is finished, the porcelain can be put back into position.
No smashing out paving.
No cutting through a patio.
And no permanently visible manhole cover necessarily sitting in the middle of the finished design.
Designing the Frame Around Drainage
We don't want the steel structure itself preventing access either.
That's why drainage is considered before the frame is installed.
When surveying the garden, we identify features such as:
Manholes
Inspection chambers
Drainage runs
Soil pipes
Gullies
ACO channels
Rainwater pipes
Other underground services
We can then consider these when planning the support and frame positions.
Where access needs to remain available, the structure can be arranged accordingly.
This is much easier than discovering the problem after the patio has been built.
What About Drainage Pipes Running Under the Patio?
Having drainage pipes underneath a patio isn't unusual.
The important consideration is future access and avoiding unnecessary interference with them during construction.
Because an iFrame patio transfers its loads through defined support positions, we can consider the location of known services when determining where those supports should go.
That can be particularly useful in complicated gardens where several drainage runs cross the proposed patio area.
Rather than automatically excavating the entire footprint, we can work with what's already there.
What Happens If a Drain Needs Repairing in the Future?
This is where future accessibility becomes one of the biggest advantages of a dry-laid patio.
Imagine discovering a drainage problem five years after installing a conventional porcelain patio.
If the affected pipe is underneath the patio, accessing it could involve cutting joints, breaking out porcelain and excavating through the patio construction.
Once the drainage repair is complete, the patio then has to be rebuilt.
With an iFrame installation, the porcelain can be lifted.
Depending on the location and extent of the repair, additional tiles can be removed to provide a larger working area.
The structure underneath remains visible and accessible.
Once the work has been completed, the surface can be reinstated.
We think about how the garden might need to be maintained in the future, not simply how it looks on the day we finish it.
Can You Hide Every Manhole?
Not necessarily.
Every drainage situation needs to be assessed individually.
There may be circumstances where regulations, access requirements, chamber position or the design of the patio mean that a conventional accessible cover is still the correct solution.
The important point is that we have more than one option.
We don't automatically assume that every existing manhole has to dictate the appearance of the finished patio.
What About New Drainage?
Existing drains are only part of the equation.
The new patio also needs to deal with rainwater.
With a traditional porcelain patio, the surface is normally constructed with suitable falls to direct water towards drainage points.
An iFrame patio works differently.
Our porcelain is dry laid with small, consistent open joints between the tiles.
Rainwater can pass through those joints into the area underneath the patio.
From there, the underlying ground and drainage strategy need to manage the water appropriately.
Where required, additional drainage can be incorporated into the overall garden design.
Drainage Around Bifold and Sliding Doors
Drainage becomes particularly important when creating patios close to the level of modern bifold or sliding doors.
Homeowners understandably want that seamless indoor-outdoor appearance.
But we also need to protect the property.
Door thresholds, damp-proof courses and surface-water management all have to be considered.
Depending on the property, this might involve suitable drainage channels or maintaining an appropriate separation between the patio structure and the building.
The objective is to achieve the clean appearance of a near-flush transition without creating a route for water back towards the house.
Don't Design the Garden and Think About Drainage Afterwards
This is probably the most important piece of advice we can give.
Before deciding exactly where the patio, steps, outdoor kitchen or planting areas are going, find out what's underneath them.
Open the manhole covers.
Understand which direction the drains run.
Locate inspection chambers.
Identify downpipes and gullies.
Look at the natural levels of the garden.
Then design the patio.
At Garden Ezee, drainage isn't something we want to discover once construction has started.
It's part of understanding the garden from the beginning.
A Patio Should Look Good – But It Still Needs to Work
A beautifully landscaped garden needs to work as well as it looks.
Drainage isn't particularly exciting when everything is working properly.
It becomes extremely important when it isn't.
That's one reason Garden Ezee's approach to patio construction has evolved.
Our experience in traditional landscaping combined with the iGarden iFrame system allows us to create patios that don't necessarily permanently bury everything underneath them.
The finished garden can look clean and contemporary while important infrastructure remains accessible below.
Got a Manhole in the Middle of Your Dream Patio?
Don't automatically redesign the entire garden around it.
And don't assume you're going to have to look at a metal or recessed access cover forever.
Send Garden Ezee some photographs of the proposed patio area, including the position of any visible manholes, drains and inspection chambers.
We'll look at the layout, levels and existing drainage and consider the best way of incorporating them into the new garden.
Comments