Retaining Walls & Excavation advice

[Cobber]

Ok - my house is getting excavated soon. Here is a diagram of my house attached. The area where the lines are are where I need to get it cut. I am on a slant upwards to the backyard so will need to put in some fair retaining walls.

My 2 questions are:

1) Should I cut the site all the way to the end of the block on the right hand side. If I dont it will mean it will higher on that side but I figure I could do some landscaping and make it look good. Or I could juts cut it all the way to the fence?

2) Retaining Walls - whats the best way to do it...timber sleepers or is there a product that I can buy (I saw someone mentioned Keystone).

Thanks Cobber

[TassieKiwi]

More info required:
Type of soil
Height and angle of cut face
presence of groundwater - enemy#1 for walls
Amount of runoff of rainwater from ground above cut, including neighbours.

As to the shape of the cut, the more you dig the more it will cost, but the wall will be about the same area=same cost. Al depends on the final use of your yard - how do you want it to look?

Piccies would help too.

[ernknot]

You forgot the shed.

[JDub]

In most areas retaining walls over 1m will need engineering approval/plans etc

Dont use timber if its a permanent feature as it will rot eventually and will need replacing. The Boral and C+M brick retaining wall systems are pretty good (I used C+M Ab Aussie blocks and was very happy)
http://www.cmbrick.com.au/retain.html

Again in most areas Im pretty sure you cant cut right to the boundry fence without approval... could be wrong on that one though ;)

[TassieKiwi]

In most areas retaining walls over 1m will need engineering approval/plans etc

Dont use timber if its a permanent feature as it will rot eventually and will need replacing. The Boral and C+M brick retaining wall systems are pretty good (I used C+M Ab Aussie blocks and was very happy)
http://www.cmbrick.com.au/retain.html

Again in most areas Im pretty sure you cant cut right to the boundry fence without approval... could be wrong on that one though ;)

Also, some of the big suppliers have a free design service for small walls.

[Cobber]

Thanks everyone. I dont have photos yet. Part of the cut is low but the part in white would be a 750mm cut I reckon. If you look at the document attached I will not cut it all the way to the fence meaning I will need to put steps in and that area to the right and also to the north will be higher than the cut area which will be a deck or paving. Its confusing I tell you. I will need to put in aggy pipes etc for the drainage as well. aaagghhh

[Cobber]

By the way whats the cost of these retaining walls at CM Brick

[Gumby]

I used this. It's not cheap but it's forever.

http://www.australbrick.com.au/vic/product_10_linkwall.php

The heavy vertica blocks are 50kg each !

[Cobber]

I reckon I might go for treated pine and H pieces for a retaining wall....should be cheap hopefully...what do you think. Anyone done this recently.

[Gumby]

It depends on how long you want it to last.

[tcns]

I would not build it out of pine unless you are keen on doing it again,

boral heathstone - see my posts about it - good solution and fairly good value I think treaded pine is an expensive way of doing it because it will have to be replaced

Tom

[tcns]

Oh and the heathstone are a true vertical stacker and are ok to 800mm without engineering and weigh 25kg which is bloody heavy.

Don't know how you would go about using those 50kg ones I am flat out
moving the 25kg ones in any volume. I put 300 blocks down for my walls
and had to move them by hand from the front to the back of the house and then place them in the bottom course and level them in all directions over and over again .....

Tom

[Gumby]

Oh and the heathstone are a true vertical stacker and are ok to 800mm without engineering and weigh 25kg which is bloody heavy.

Don't know how you would go about using those 50kg ones I am flat out
moving the 25kg ones in any volume. I put 300 blocks down for my walls
and had to move them by hand from the front to the back of the house and then place them in the bottom course and level them in all directions over and over again .....

Tom

I carted 25 of the 50kg buggers from the front of the block, down to the back and then realised i should have left them up the front. They are bloody heavy. :eek: But in a wheelbarrow, not bad.

Cobber,you should go to the brickworks and look at the displays they have set up.

[ian]

Cobber
what sort of dirt are you excavating?
what are your local council's requirements? arround here you need Council approval for what you propose and Council's regs sort of set the bench mark.

as to your comment
I will not cut it all the way to the fence meaning I will need to put steps in and that area to the right and also to the north will be higher than the cut area which will be a deck or paving. Its confusing I tell you. I will need to put in aggy pipes etc for the drainage as well. don't forget that it will get real expensive and real nasty real quick if next time it rains your retaining wall fails and takes the neighbour's fence with it. A bloke a dozen doors up from dad put in a "home designed, she'll be right" retaining wall -- after a week's solid rain he was up for a $30k replacement plus reairs to the neighbour's back yard.

ian

[Cobber]

I assume the dirt is clay. Ive got the Soil Report at home but just quickly looked over it. At this stage I am budget conscience so I believe (correct me if Im wrong please) that treated pine will be the way to go. I will need to get the drainage right of course.

If it last 10 years then thats fine...that gives me 10 years to worry about something else and by then I will be able to afford to pay more for another better retaining wall.

My old man reckons he know what to do using sleepers and steel H bars...concrete the H bars in the the ground and then just throw the sleepers on....when they rot just pull them out and replace them........

[tcns]

I would price up both options and see - there are various usage/estimating calcuators available on the boral website - check it out and compare the price, treated pine was not a cheap as I thought it was going to be

Tom

[ian]

If it last 10 years then thats fine...that gives me 10 years to worry about something else and by then I will be able to afford to pay more for another better retaining wall.what looks like a viable plan might not be in ten years time when there is buggerall access to dig the foundations for the replacement wall so it all has to be dug by hand.

also, what are your local council requirements? I find it hard to believe that the scale of what you propose can be done without Concil approval and by inferance your Council will set the minimum requirements.

lastly, the reason engineers charge so much to design anything is that they essentially remain liable till they die for what they design. For a biggish stuff-up on a home designed (she'll be right) wall there is no statute of limitations and the agrieved party (often the insurance comany)will go looking for the culprit.


good luck with your extension.

ian

[Cobber]

I always thought you need engineering and council approval if the retaining wall was over 900mm???

[petersams]

Ok - my house is getting excavated soon. Here is a diagram of my house attached. The area where the lines are are where I need to get it cut. I am on a slant upwards to the backyard so will need to put in some fair retaining walls.

My 2 questions are:

1) Should I cut the site all the way to the end of the block on the right hand side. If I dont it will mean it will higher on that side but I figure I could do some landscaping and make it look good. Or I could juts cut it all the way to the fence?

2) Retaining Walls - whats the best way to do it...timber sleepers or is there a product that I can buy (I saw someone mentioned Keystone).

Thanks Cobber

I suggest that you should not cut the site all the way to the end of the block instead make it look good by having a little garden or doing landscaping. If you are planning to build a retaining walls in your backyard there are companies that offers retaining walls products. Retaining walls can be made from all kinds of materials like wood, natural stone, and concrete. Just choose whatever you like. After all it's your own choice.