Experts' advice urgently needed on the type of sand near the foundation

It’s hard to know how to respond - you seem to be overly anxious about this. Also, the purpose of the gutter is to get rid of the water from the roof. Nothing else.

As mentioned previously just let the soil dry out first.

And make sure the gutters and downpipes are clear. And that you have sufficient down pipes to cope with heavy rain.

Even then, if the down pipe overflows in a huge storm (rarely I mean) it’s not the end of the world.

The publication that I linked to is covering a range of issues that might not be relevant to you (e.g. clay soil.)

 

Thank you for the reference, so much info we need to read and learn there

You pointed a new direction to us that we've never thought before.

We're thinking the way is to seal the area, but in fact, it might not be and even dangerous.

If we find someone to start a sealing project and he isn't aware of other drainage risks and factors, that can be a big problem

Then the question is, which profession can think and assess the whole situation correctly? (Soil close to the foundation + Drainage risk of backyard + Gutter and downspout system of the house)

We should find a plumber? or, a landscaper? builder? which profession is more relevant?

Many many thanks

 

That is your best long term solution.
Make sure the path levels fall away from the house.

 

Thank you for the images you have provided @henry_ip , they confirm my suspicions about water flowing downhill towards your house. At the back of your house, the house is built right on ground level with all that land sloping down towards the house.

You will need to take your new drains all the way around the side of house too and connect them into the stormwater pit. You will also need to make the drains large enough to do their job correctly. Refer to the design you posted from QBCC in post #19.

My guess is you need a plumber or a landscaper to drain away water seeping through the retaining walls. As the others have said this property will possibly require additional downpipes and additional drainage to cope with tropical rain like we are having this week. It will all dry out later. Getting appropriate drainage in the space between the retaining walls and the house will fix your problem with wet soil against the house. You can get this area concreted all the way across the back at the same time as the drains are installed.

Be careful if walking around on your roof as it will be slippery and the weather may get windy later.

 

Yes.. it can be dangerous, hopefully the tropical rain can be over soon so we can work on the gutter more safely..

If we want to do something for temporary relief in a cost effective way, do you think we could diy and install "partial french drainage" - a 65mm ag pipe to prevent the water flowing through the soil from the retaing wall to our bedroom foundation:

Reln 65mm x 7m Slotted And Socked Stretch Ag-Pipe

 

Joynz, the attached image is our gutter. The width is only around 5cm.

When compared to the ones we watched in youtube, it seems too narrow?

As we learnt the gutter and downpipe are the first line of defence and play important roles, do you think its worthy to install a wider gutter for larger capacity to handle the rainwater?

 

Have you asked a roofer, or at least a handyman, to look at it and give suggestions?

 

Hi trainee, its our first house and we wonder if we should find a plumber, or roofer for gutter advice? Roofer is more specialized?

Would that be likely the roofer will sell us to install his products without being objective?

 

This is self-diagnosing a disease by reading the internet when you should be talking to a doctor. And then not trusting the doctor.

You are worried about the issue. Looks like a genuine issue. You can't DIY, by the sound of it. But you don't trust tradesmen or don't trust yourself to interact with them effectively.
Why haven't you asked for recommendations on tradesmen to talk to in your area?

You can't be scared of a problem and also be too scared to hire someone to fix it.

This is clearly a pattern on your part. Maybe work on that? Long term cheaper than treating your insomnia.

 

HI trainee, we have contacted local several plumbers and concreters yesterday night and they will probably call back to respond to our enquiries tomorrow. The reason we asked question in this forum is we find this forum is a really good place to learn from other's experience. Without this thread, we wouldn't have any basic knowledge at all and we feel a bit better to do some homework first.

Yes we are a bit paranoid porbably after watching too many 60 Minute interviews and news reports revealing some of the unfortunate house owners who ran across some dodgy tradesman

 

Then why didn't you ask the forum for recommendations? Not like you have to say the suburb.

 

Asked in several local suburb facebook groups and got a lot of immediate responses from the friendly neighbors, so we already contacted those recommended tradesmen. While we are contacting those trademen, we would keep learning relevant knowledge from experienced users here to minimize the risk of being scammed

 

You need advice from a roofing plumber.

 

G'day Joynz,

Just want to update our progress, we cleaned the gutter and (the roof as well!). Clearly see a difference with no debris blocking anymore. Just can't describe the feeling when we see some progress finally.

At the same time, we've arranged the plumber to help us next week since this week we dont have anyone at home in daytime.

That means we need to prepare ourselves for the next rainstorm coming soon.

We have cleaned the gutter, so, how about downpipe?

Problem is how do we know how fast the water drains to ascertain the condition of the downpipe?

We wont know if the overflow is either caused by 1) lack of downpipe with heavy rainfall or 2) blocked downpipe?

It seems a bit dangerous to climb and obeserve the gutter during heavy rainfall. We dont have a hose to test the drainage of the gutter. (A bucket of water is too insufficient)

Our question is, as it's hard to see the condition of (esp the bend) of the downpipe, do you think its a good idea to pour some sodium chemical into the downpipe regardless of blockage or not?

Please see the attached images - the product we bought and our downpipe

 

You do not unblock gutters with chemicals. The picture on the product you posted shows that that product is for sinks which can get clogged with fats (though I would use a plunger or unscrew the u bend rather than use harsh chemicals for a sink blockage).

Fats are not a problem for down pipes. Down pipes get leaves stuck - usually in the ‘elbow’. After some time, they decompose and turn to earthy mud.

I think you should ask the plumber to check.

But if you can’t wait, buy a hose and run it into the gutter. You should hear how fast the water drains. if you hop on a ladder, you will see if the flow is strong.

It looks from that photo that the downpipe is angling up rather than down (the short section under the eaves). Is that correct + or just a bad photo?

As you are still learning, it might be best that you get a plumber to check the downpipes. They have all the equipment needed. And you can be sure they are clear.

 

@henry_ip

that's what it looks like to me too.

and that S-bend in the photo is going into the sewerage system hopefully to be treated further down the line.
your rainwater that is caught by the roof, gutters and downpipes flows down to the street then to the local creek, stream, river, or ocean.
do you really want to discharge chemicals directly into your local creek ecosystem.
sewerage and stormwater are not the same.

I think everyone has given great advice so far and depending on your location, cleaning your gutters should be something you do regularly. it's just part of general home maintenance.

just as @Joynz has suggested - you should buy a long hose and turn it on full into the downpipe. Let it run. Then walk out front to the street and look for the discharge point in the kerb. watch for all the leaves and dirt run out. (most properties have this unless it drains directly underground to council pipes)
it should be flowing freely down the kerb and gutter. if it isn't you might have a blockage somewhere. then if you're not confident clearing it, pay a Plumber to clear it.

job done. crack a XXXX.

collection and discharge of your rainwater from your roof is half your problem solved.
then you can work on the overland flow (maybe with some help, as others have suggested)

 

Hi Joynz, just want to update a bit. First of all, really thankful for your alert.. we almost poured in chemical into the downpipe.

So we managed to get the plumber to come and inspect a few days earlier than arranged and we finally have more clues of what happened:

Photo:
grading

1) Underground drainage pipe blocked (the yellow part)
Unfortunately right under the brick paver. That means we need to take the brick out and the plumber can come and replace the blocked pipe for the next visit

2) Gutter is sagging and need rescuring
The plumber will come and also resecure the gutter next time

Suggestion:
The plumber also tell us how we should grade the area (blue arrows)

Though when we use a shovel trying to move the earth for grading, we find the soil is quite hard and difficult to dig. Do you suggest we should get a tiller?



Or we should find some cheap labor to help us?
15+ Best Rated Landscapers Near You (Free Quotes) | Airtasker

Thanks again,
Henry

 

It’s hard to be sure, without knowing what kind of soil you have. Also depends on your budget.

It can be done with a spade (not a shovel) - but might take a while.

If you want to use a spade, you may have to jump on it to get it into the soil. I have a long handled spade with a ‘lip’ on the top of the blade that I can push my foot against (or sometimes jump on) when the soil is tough.

I have also used a tiller to help a friend till packed clay - and it was pretty hard going too - but we managed it eventually. Perhaps rent one for half a day to see how you go.

if you hire a landscaper, be very clear (in writing) what you want. And only pay when you are certain the it has been done correctly - with the correct grading.

Be careful with airtasker - airtaskers are often unqualified and may not actually know how to grade soil. Or what slope to grade it to. I would probably use a more professional service seeking site. Can your plumber recommend someone? I notice that people often post on the local Facebook community hub asking for recommendations too but I don’t know how reliable that is.

Call Dial Before You Dig to make sure you (or they) don’t dig over cables (they should be pretty deep, but worth checking). Also, watch out for plastic garden irrigation pipes in the soil.

Has the plumber suggested any other drainage?