DIY lawn and garden drainage guide

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Information on this page

How to install garden drainage.
Materials you will need.
DIY Information sheet.
Testing a waterlogged garden.
What are the main reasons for waterlogged garden problems?
How can I drain water away and fix a waterlogged garden and soggy lawn problem myself ?
Tools needed to install garden drainage and dig the trenches.
Using prefabricated soakaway drainage baskets and crates.

Follow this link to;

Check out my drainage guide

Or ask Mike about our

Drainage services

Can I fix a waterlogged garden problem myself?

Yes you can drain and dry out a muddy, soggy waterlogged garden even on clay soil by installing the French drain system described here.
So if your fed up with the mud follow the tips on this page and the guide featured below and you really can do it yourself.

How do I know if my garden is waterlogged

Testing for a waterlogged garden.

The soggy problem will probably be obvious, puddling, squelch when walking, reed like plants growing in the lawn, moss and muddy kids.

If not carry out this simple diy test;

Dig a hole 24 inches deep x 12 inch square and half fill it with water. Leave it for four hours. It should empty on well-drained soil, if it doesn't or if it fills and it hasn't rained, you have a drainage problem. probably on clay soil.

Even in well drained soil, water will not soak away fast enough during periods of heavy rain and will run across the top of the lawn to the lowest point, a process that is known as puddling.

If it doesn't soak away within 4 hours you have got a drainage problem, possibly clay.*

If the surface water drains away slowly the garden may just need aerating

*If you suspect the problem might be clay, carry out this simple test to find out what type of soil you have.

Follow the tips to dry-out your boggy garden

What causes garden drainage problems?

Common causes of a waterlogged garden

All sorts of factors can contribute to a waterlogged, soggy garden and these are the 10 most common causes I have found ;

Heavy sustained rainfall can cause underground springs to change direction.
Compacted soil combined with the mixing of subsoil and topsoil when the house was built is a very common reason for soggy spongy lawns.
Clay soil. You can't blame it all on the builder, it's more likely the house and garden have been built on clay (easily recognised because the surface cracks up when it is dry). Not easily avoidable however, as great swathes of the UK consist of clay soil.
The garden is lower than neighbouring gardens or at the bottom of a hill. Water flows downwards and unless it has been dealt with upstream by installing a drainage system to catch or divert the water, is naturally going to be a problem downstream. It's not really your neighbour's fault that this is happening.
Structures like swimming pools, home extensions you or neighbours have added can all cause gardens to flood. Anything with deep footings can divert water.
Uneven lawn or garden surfaces. On clay and other water retentive soils, the flow of water through the soil is very slow made worse by dips in the surface allowing water to puddle and flood during heavy rain.
Hard landscaping. The increasing use of impermeable materials to construct car parking, driveway and patios is a problem. Rainwater that should be soaking into the ground runs across the hard impermeable surface into the property and gardens below it. If you are unlucky enough to live next to (and lower than) a tarmac or concrete parking area, you could try asking the culprit to install a French drain on their side to catch and divert the water away from your property.
Is it the Water Table? Some water table information here.
Gutters and down-pipes not connected into the drainage system (or blocked) instead discharging onto the garden or patio. Always connect the down-pipe into a drain.
Diverting water into your property. If your neighbour has recently installed a garden drainage system check that it is not terminating at the boundary between your properties and discharging water into your garden.

A lot of time and money can be spent trying to trace the water source, leading to disputes with neighbours, the surveyor and builder who built the extension, the landscape gardener who installed your paving and retaining wall without considering the effect on soil drainage.

Solution? for most waterlogged garden problems the only solution is to drain the water away.

Use my D.I.Y garden drainage guide together with the information on this page and my other linked pages to install a simple and low cost gravel drainage system to drain your soggy garden.

Lower down this page I have also included some common DIY mistakes that won't dry out your garden and lawn.

How to install DIY garden drainage.

What DIY garden drainage system will work to dry out a waterlogged garden and lawn?

A gravel drain trench system (French Drain) installed below the surface, solves most garden drainage problems. Ever since the Romans used them to solve drainage problems, not much has changed, perforated plastic pipes (holes at the top or bottom, depends who you ask !) came and went, French drains still work.

Why are they are called French drains? Although stone drains go back the Ark, they are actually named after an American, Henry French a 19th-century judge,gardener and farmer.

Can I fix a waterlogged garden and soggy lawn problem myself ?

Yes with the right tools, including a trench spade, trench shovel, spirit level and a trench hoe that are preferably made for trenching and sturdy enough to lift clay. (I have featured the tools I use, further down this page)

You will need to enlist the help of a few fit friends and neighbours and if you have access, hire a digger or set aside few weekends digging trenches in clay soil, lugging a few tons of gravel into your garden and getting rid of an equal amount of clay, what goes into French drains must come out first.

Installing French drain style garden drainage is not rocket science, It's mostly common sense (water will only flow downhill) and hard labour, digging trenches, taking tons of clay out and wheelbarrowing the same amount of gravel back in.

Following these D.I.Y. garden and lawn drainage tips will help. Depending on how your garden slopes the different DIY methods described here will stop water logging.

Herringbone drainage

Herringbone drainage works for lawns and gardens that are waterlogged over the whole area.

Mark out the main trench from the highest part of the lawn, to the lowest.
Mark the side trenches to connect to the main drain, forming a herringbone pattern. The side drains join the main drain at a 45 degree angle.
Space side drains at 10 ft intervals for clay soil and 25 ft intervals for loamy soil
Dig out the trenches to at least 18 inches deep, saving about 6" off the best clay free topsoil to backfill.
Line the trench with landscape fabric to keep earth out of the gravel to allow water to percolate through easily.
Shovel coarse 20 ml gravel onto the landscape fabric leaving 4 to 5 inches to back fill and fold the fabric over the top of the gravel.
Shovel or rake the topsoil you have saved back into the trench, slightly over filling to allow for settling.
At the lowest end of the main trench dig out a soak away at least 4 ft deep and link the main drain to the centre of the soak away. Bear in mind if you hit clay when digging out the soak away it's not going to work and you will need to look at either connecting into the surface water drain system or installing a sump and pump

Single French drain.

Used to drain water away from a wet, soggy or waterlogged part of your garden to a soakaway or drain.

Slope the French drain to carry the water down to its destination. Dig the trench across the waterlogged area and then towards the soak away. This type of drain need only be about 6" wide and 12" deep. Before filling with gravel, line the trench with landscape fabric to keep earth out of the gravel to allow water to percolate through easily. Shovel 5 to 7 inches of 20 ml coarse gravel onto the landscape fabric. Wrap the fabric over the top of the gravel and top up with soil.,

Soakaway drainage trench

For lawns that are level, not on clay, not compacted and water lays on the surface, a soak away trench could work. Dig a trench about 2ft deep and 2ft wide along the length of the lawn. Line the trench and partly fill the trench with about 12in of clean brick rubble, then 8 ins of gravel and top up with soil. Soakaways won't drain away in heavy clay soils. Worth aerating the surface first, might just be compacted!

For any type of drainage system that is installed below the surface of a lawn or garden to work to full capacity, the surface needs to be kept aerated.

Aerating the lawn, helps drain away surface water. Aerating Tips and tools

Bog area & water feature. You could try making the most of waterlogged areas in gardens and lawns by installing a bog garden area filled with colourful bog plants, I have listed a few here garden ponds.

Mikes easy to follow Garden and lawn drainage D.I.Y. guide

Drawing on years of experience this easy to follow guide shows how to Install French drains.

Marking out and digging trenches
Finding lowest spot for positioning the Soak away.
Materials and Quantities (how much gravel) to form the drains.
5 mins free Telephone back-up
Simple easy to follow steps
Terms

PDF normally Emailed within the hour or 8 hours if i'm out of the office

£10.00. Converted to $ and € or local currency outside the U.K

Happy user

Just completed the drainage on my lawn using your diy guide, must say it was simple to follow still hard work, but what a difference, my boys can play on the lawn again, and I did save a lot of money. I found the gravel calculator really useful, ended up with a bit left over but probably my calculation.

Thanks again and for the chat on the phone (well worth a tenner)

Jason. Leeds

name and address supplied

Tools and materials to dig and make drainage trenches.

Tools you will need to dig drainage trenches.

Digging drainage trenches is a lot easier if you use the correct tools.

Strong rake, Drain spade, Trenching shovel, Digging Hoe.

Rake 1500 mm

Over the years I have broken more ordinary garden rakes raking clay than I care to remember. I have used this Heavy duty all steel rake for years and it is still being used by my team.

It is strong enough and suitable for raking and breaking up heavy clay soil.

Forged Trench Shovel, 970 mm

Heavy duty forged steel head Tubular steel shaft and MYD handle Heat treated for durability For digging and bottoming trenches Blade L x W: 270 x 165 mm

Forged Drain Spade, 1150 mm

Heavy duty forged steel head with extended shoulders for safer foot-grip. For digging drain and pipe channels, trenches and fence post holes.

Materials for garden drainage.

Woven Polyproylene fabric with 40 securing pegs usefull for holding the fabric in place when shoveling in the gravel. Lets rainwater through and is essencial in keeping the soil out of the gravel.

20mm Gravel/Shingle (Bulk Bag) with free delivery in UK

This is the type and size of gravel you will need to fill the drainage channels.

As an alternative to using gravel consider the prefabricated crates below.

Pre fabricated soakaway and trench baskets

The pre-fabricated soakaway system offers an alternative to gravel when installing a French drain garden drainage system. Crates measures

800x500x540mm = 0.216m3 Volume

Sump pump information on my Sumps and Pumps page

Pre fabricated soakaway and trench baskets

The crates are wrapped in a special geotextile fabric which allows water to soak through into the crates, but keeps soil out. They can be used in exactly the same way as traditional gravel filled soakaways and trenches.

Dig out the hole or trench to the required length, width and depth, then place the wrapped crates into the soakaway hole or drainage channel. Connect any pipe work and back-fill with soil.

What won't work to drain and dry out a waterlogged garden

These are some of the more common garden drainage DIY errors;

Removing the top six inches of clay topsoil and replacing it with new loamy soil doesn't solve the underlying water logging and soggy lawn. It just hides the problem for a while, before turning into a big spongy, waterlogged mess the next time it rains, or at best, shifts the problem to another part of your garden.

Replacing the topsoil can work, if the new soil is separated from the water. More information can be found on my raising flooded garden page.

Soakaways on clay don't work, The hole will fill up and flood, consider alternative ways of getting rid of the water. Sump and Pump

Planting trees or shrubs in a soggy area of your garden won't work, unless you are planting bog plants because the roots need to breath, they will eventually die. Willows grow on the bank not in the stream.

Adding topsoil without a proper hardcore or gravel base doesn't work, you will end up creating one big sponge or just shift the problem to another area of your garden or to a neighbour.

Raising the whole area by adding raised beds or a substantial bed of rocks or gravel topped up with topsoil can work, but because the water is still there, the danger again is shifting the saturated soil problem to another area.

Soakaways and alternative ways of water dispersal.

In gardens that slope away from the house it may not be possible to connect the gravel drains directly into the surface water drainage system and the rain water may need to be drained into a sump and pumped.

I have included some basic information on the drainage sump and pumps page. also some other drainage systems you may want to consider.

Do not connect into the Foul drainage system: this is the drainage system that removes the waste from the toilet, bath, sinks, washing machines, dishwashers and showers and you will need permission from the local authorities and like everything with councils that could take forever and ever and ever.

You can connect into the surface water drainage: this is the drainage system that deals with rainfall from your gutters etc. Some authorities will require you to seek permission. .

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