How to fix downpipes and storm water issues?

[JayADL]

Hi, we bought a 1970s home in Adelaide a couple of years ago. The pine floorboards have big dips and there’s cracking throughout the home. 
Our rectangular house has downpipes on each corner but they’re not diverting water away from the home and are believed to be cause of our wall cracking/flooring issues. 
Picture 1: Front left downpipe (left when looking directly at front of house)

Picture 2: Front right downpipe

Picture 3: Back left downpipe 

Pictures 4: Back right downpipe that runs onto the top of our shed (most significant damage to house stumps on this corner. Earth is wet underneath. Also the lowest corner). 

We’ve had a plumbing company come out who have recommended that the two downpipes on the front of the house to be connected to the street storm water. Our ground is higher near the footpath and continues to slope down towards our house and across our property to our back fence. I questioned how the water can flow towards the storm water as water doesn’t flow uphill. Do they lay the pipe underground on an angle? He replied that the pipe will be laid level and water will always sit along the bottom of the pipe.

He recommended that our back downpipes be connected to a new rainwater tank (runs off our shed) but doesn’t believe a rainwater tank will be enough. Estimated price will be emailed soon but have been told it will be a ‘shocker’ due to the many difficulties. Would very much appreciate a second opinion 😊

 

   

[JacobZ]

Hi @JayADL,

Thank you for your question and welcome to the Bunnings Workshop community, it is fantastic to have you with us.

It looks like a complex issue that will require careful consideration to fix completely. Your plumber's recommendations sound like they are probably the best way to go, but this isn't to say it is the only thing that can be done. 

Any time a connection needs to be made to council stormwater, plumbers are an unavoidable expense, and the unfortunate reality is that plumbers are one of the most expensive trades. 

This part of the job seems unavoidable because currently, your downpipes are discharging onto a hill that runs back towards your house. To me, this is a critical issue that needs to be addressed.

In the process of installing stormwater pipes, you could also have some drainage channels run along the front of your house to capture any water that is flowing down towards your home from your front yard and the street and divert it away from the foundation.

Does your backyard flow away from the house? 

If so, this part of the job seems less critical in protecting your home from further damage. If the cost of installing the stormwater in the front yard is high, you could potentially put the backyard on hold till you have the funds for this part of the job.

Remember there is no harm in shopping around and getting a few quotes before deciding who to go with. Make sure you ask for a breakdown of their recommendations so you can compare what they are proposing to do, not just the cost of the job.

Allow me to tag @Dave-1, @Noyade and @Nailbag to see what they think.

Let me know if you have any further questions.

Jacob
 

[Dave-1]

Afternoon @JayADL 

A couple more questions  

The house level at the ground is how far below the street?

There is a house pretty much how I picture the slope of your land and where it sits below the road on the highway in my suburb.

They solved their issue of water in the pipe sitting or backing up by running it along the fenceline level (well a tiny slope) with the street outfall.

Cant really take a photo of someone else place lol

But they had their downpipe go down then across the yard to the fencline and then to the street. Very little digging involved. If this is an option I wouldnt attach it to the fence I would make my own supports up to hold the pipe in place.

The rear downpipes, well the right hand side could join to the one going to the street. The left could still go to a water tank (just larger) that depends on if you use the tank water? Where does the water from the sheds roof end up? Maybe you could do the same think along the fence line on the other side of the tank? I do like the idea of a large water tank espically if you use the water activly

Last bit

The water running down the hill towards and then under the house. A trench with either a grill drain or dish drain and a sump styled pit at the end of the drain to pump the water to the stormwater pipe and to the street is something I would install. Keeping the underside of the house dry may mean a bunch of earth works to divert the water flow elsewhere.

Dave

[JayADL]

Thank you for your time.

At a guess, the base of our house is probably no more than 30cm lower than the ground level near the footpath. It’s a very slight slope. However, from the back of the house to ground level is much more significant, probably 1.5 meters. 
When looking at the front of our house, not only does the block slope downwards (slightly to the house, significantly from the back of the house) the block is also higher on the right side. So the back left hand side of the property (where the shed is) is the lowest point. 

When you say that a house in your suburb connected their downpipes to a pipe that ran along their front yard (fence line) does that pipe go under the footpath to connect to the street stormwater? Or discharge onto the ground in their front yard?

I’ve since spoken to a few neighbours on our side of the street and no one has pipes running under the footpath to the street stormwater. People have just added PVC piping to their downpipes and have the pipe running on top of the ground to the very front of their front yard. In their backyard they have it diverted to rainwater tanks. This seems like the cheapest and easiest solution, but not sure if it’s the best. 

[Nailbag]

Hi @JacobZ 

I would follow the excellent advice already provided by @JacobZ in capturing as much rainwater as possible and getting at least two more quotes. It's often quite surprising how different the same job can end up in both pricing and ideas. The main reason any plumbing can start to sky-rocket in value is when any escalation is required either manually or by machine.

Nailbag

[EricL]

Hi @JayADL 

Just to add to the suggestions made, I propose adding two slim five thousand litre tanks at the back. In this manner you maximize your water storage capacity and have the overflow of the tanks pointed to the back of your property or piped towards the storm water drain. This will at least reduce the number of channels to be dug.   

If you need further assistance, please let us know.

Eric

[Dave-1]

Good Morning  @JayADL 

The one that I was refering to has the pipes go through the footpath (underneath) If possible I will try to casually walk by and go "click" with the camera lol

A lot of older styled homes have the same issue, The old suburb I grew up in is like you are describing it now that I think of it The stormwater must have run down the back to the creek! Man the things we take for granted!

The larger tanks may be an solution, A sump pit could also do the job but requires power to run. I like the idea of along the fence line. I would strongly suggest to get a plumber to do the bit across the footpath. (I live in NSW and my plumber said there was no issue for me to do it. Other states may have differant rulings and also local council rulings could be differant as well) but I fear if I hit any cables or services in the shallow trench then it would be headache time plus.

Dave