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How to stop roots growing into our house and water ingress?

We moved into our house in 2019 and on 2 occasions since then our lounge room has flooded during heavy rain / cyclonic weather over 5 days. We really want to try and avoid this happening again! We think the rain comes in because right next to the house are 2 garden beds. Until recently, one of the garden beds had 3 camellia trees. It has taken us weeks to get to the stage in the photos as camellia roots are as hard as steel and they have grown into the brick wall and under the concrete. We think the best thing to do is to lay crusher dust, then sand then pebbles. However the concrete already down seems to cover half the weepholes for a short distance. Are we OK to go ahead with our plans for a pebble garden or should we take up the concrete which is half way up the weepholes? Should we seal the wall before filling with drainage gravel? How deep do we need to dig?

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Comments

AlanM52

Hello @lpr2468,

That's a serious amount of water coming in, I would halt the project and raid the piggy bank to call in someone like a drainage plumber to inspect and advise. Maybe those roots have caused water damage away from the house and the water is pooling there?

The other option is to line the back of the garden bed with boards secured with star pickets so you can tidy up to make it look respectable.

Then just sit and wait for a similar weather event and check what's happening in the trench.

Cheers

JacobZ

Hi @lpr2468,

A warm welcome to the Bunnings Workshop community and thank you for your question.

I'm sorry to hear that you have had ongoing issues with water ingress at your property.

If you are getting considerable flooding, then there is likely more than one issue that will need to be addressed and I would put a hold on the project until those issues are dealt with.

Considering the extent of the issue, as @AlanM52 has said, I would suggest it is likely worth getting a drainage plumber out to inspect things.

It seems likely that the height of the concrete around the house would be an issue. If the weepholes are covered, this means the concrete is also above the height of the dampcourse, meaning any water that runs up to the house during rain events can wick into and through those bricks. Without looking at the property myself, it seems likely that some landscaping would need to be done to reduce the height of the concrete and possibly the natural soil around your property so it sits lower.

You may also need to look into installing suitable drainage around the perimeter of the house so water is not able to pool against it. Heavy rains happen, so equipping your house to manage that eventuality is definitely in your best interests.

Hopefully, the issue is not as bad as it sounds, but it definitely seems like something you should have a professional out to inspect.

Allow me to tag @Dave-1 and @Nailbag for their thoughts.

Jacob

Nailbag

Hi @lpr2468

Its very surprising that due to some of the key points your have mentioned, water ingress hasn't been a common occurrence. Regardless the two most important things that need addressing are:

1. The covered weep holes within the brickwork.

2. The tree roots that have grown within the brickwork and under the concrete path.

I would regard these issues as serious and need priority and proper attention.

1. You may need to consider cutting the concrete path and remove sections. Then re-grade the ground accounting for a redirected 100mm of concrete path accordingly so that the weep holes are a min 50mm (regulated clearance height).

2. With the roots cut and stump/s removed the roots can't cause further damage. However the ingress points to the house brickwork will need to be addressed. Something like removing the bricks to access and remove the roots, then re-establish the brickwork should be considered.

I would be more inclined to get the advice of a domestic building engineer over a plumber as there are several considerations outside a plumbers expertise. An engineer's first hand inspection will also provide a more accurate course of action in this case due to there variables.

Regards Nailbag

lpr2468

https://www.workshop.bunnings.com.au/discussion/comment/53131#Comment_53131

Thank you for your reply.

lpr2468

https://www.workshop.bunnings.com.au/discussion/comment/53144#Comment_53144

Thank Jacob, it is our worst fear that the concrete will have to come up. It is not easy to get someone to do this kind of job and I am not sure how we will go with a jackhammer.

lpr2468

https://www.workshop.bunnings.com.au/discussion/comment/53152#Comment_53152

Yes, I agree even though it's hard to hear. The weep holes are only half-covered for about 50 cm so there is some ventilation. No sign of the damp proof course from outside. The house was orginally built in 1983 in QLD. We are asking for the Building and Plumbing Inspection Report from the Council to see its specifications.

JacobZ

https://www.workshop.bunnings.com.au/discussion/comment/88773#Comment_88773

Hi @lpr2468,

Fingers crossed that it is not too bad, but it is certainly going to be worth having it assessed.

Hopefully they will be able to provide a solution that is not too difficult to take.

Jacob

Dave-1

https://www.workshop.bunnings.com.au/discussion/comment/110107#Comment_110107

Afternoon @lpr2468

Pretty much late to the party 🙂 And the crew really have pointed out most things I could think of.

Keeping soil off the edge of the house is something to consider.

Drainage from the garden beds next to the house is definently an idea as if you have clay under the garden then they are just big ponds that seem to soak towards your house.

As you have removed so much material I would be tempted to wait for rain and see what happens plus how long the "ponds" take to drain and if you get any water inside the house.

Dave

lpr2468

https://www.workshop.bunnings.com.au/discussion/comment/122407#Comment_122407

Hi Dave, so that was one of our options, to put drainage mat down then drainage gravel down the channel we have dug to stop the water collecting in the clay soil we have. I know my husband will like your answer compared to bringing up the concrete...

Dave-1

https://www.workshop.bunnings.com.au/discussion/comment/130337#Comment_130337

Morning @lpr2468

I would go as far as to use a piece of 50mm conduit and a hose down the center of the pipe as you push it under the path to cut away the soil below the path so the water has somewhere to drain to (into stormwater or a french drain type deal.

I just had a look at what a drainage mat was 🙂 Strol 30mm 0.30m² SureSoak Drainage Cell and yeah I know what it is tho still think that plus an exit for the water to drain to would be a good idea, the mat to give free drain away and the pipe to take it elsewhere in the yard.

Dave

TheHandySqirrel

Hi @lpr2468,

in our case the issue was not as severe: A previous owner had raised a path next to our house and in the process bridged the damp proof course (DPC), allowing water to rise in the walls.

Check where your DPC is and if it might have been compromised. From the second photo it also looks like the mortar between the bricks might have leached out where it got wet.

In our case I added mortar to where it was missing, then applied two layers of bitumen paint (this one is water-based which makes easy tool cleaning) just below the DPC.

Good luck!

lpr2468

https://www.workshop.bunnings.com.au/discussion/comment/53360#Comment_53360

Can I ask a stupid question? How do I know where the DPC is?

JacobZ

https://www.workshop.bunnings.com.au/discussion/comment/53360#Comment_53360

Hi @lpr2468,

Definitely not a stupid question as it is not exactly common knowledge.

They look like this when they are rolled up Cagroup 230mm x 30m x 500um Plascourse. Older versions may look slightly different, but you are basically looking along the horizontal mortar lines close to the ground for something that will appear as a line that is not mortar.

If you can see weepholes, it should be along the horizontal mortar line directly below them.

Let me know how you go. Happy to help further if required.

Jacob

lpr2468

https://www.workshop.bunnings.com.au/discussion/comment/88879#Comment_88879

Is it possible we have not got one? See the photo.

The house was built in 1983 in QLD. The pink chalk shows the weep hole layer. Below that it shows high on the moisture sensor....

JacobZ

https://www.workshop.bunnings.com.au/discussion/comment/110171#Comment_110171

Hi @lpr2468,

It's certainly possible, but the way the bricks stop being wet just below that course of bricks makes me think there is one there.

Could I trouble you to take a photo from lower down showing this particular mortar line?

There's a good chance this is where your dampcourse sits.

Jacob

lpr2468

https://www.workshop.bunnings.com.au/discussion/comment/122442#Comment_122442

Hi Jacob and thanks for your continuing support. I have taken some more photos. The lounge room wall is where the water comes in and we know the camellias have grown roots into this garden bed which we are still removing. We think the garage wall has no weep holes or dpc as it is just a brick wall. We have not had flooding in the garage.

JacobZ

https://www.workshop.bunnings.com.au/discussion/comment/130359#Comment_130359

Hi @lpr2468,

I can see some evidence of a damp course in your third and fourth photo.

Ensuring any natural earth or concrete that sits against the wall is at least 100mm below this level is going to be paramount to preventing further water ingress. If the soil or concrete is in contact with the bricks above this line, it can and will transfer up through the bricks and into the cavity behind the wall.

Digging down further to see what the roots have done is going to be important to understand what steps we need to take moving forward.

If you can expose the concrete below this garden bed, fill any obvious holes in the slab with a repair mortar and close up obvious seams where water could get in, you should be able to apply a below-grade waterproofing membrane such as this Crommelin Exterior Grade Brushable Waterproofer to help prevent further water from getting in.

If you can expose the concrete foundation and upload some photos, I will try to assist further.

Let me know what you think.

Jacob

lpr2468

https://www.workshop.bunnings.com.au/discussion/comment/135274#Comment_135274

Hi Jacob, we have found the dpc on the garage wall at the same level as the lounge room wall. I have concluded that some of this concrete needs to come up so we can level the paving 10cm under the dpc as there is no way around this. I am so annoyed that whoever laid this concrete has damaged my house. We are trying to figure out how much concrete we need to bring up to maintain the slope of 1cm per metre we need to run off the rain as the corner of the lounge is laid correctly 10cm under the weep holes. The pool fence is sunk into this concrete and it goes round half the house.😡 That is a lot more digging... a lot. I will put a string line to measure the slope once the concrete is up to check the level is right.

JacobZ

https://www.workshop.bunnings.com.au/discussion/comment/138561#Comment_138561

Hi @lpr2468,

It's a huge pain, but at least you have a better understanding of the issue and a clearer plan of how to fix it.

Let me know if there are any other ways I can help.

Jacob

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