Steep incline garden - want to start anew for Duplex - what are my options?

Hi everyone,

This is the backyard of a house I own which I intend to subdivide down the middle for a duplex.

Preference is to start anew and have nice neat backyard with as much usuable space as possible. Problem is that backyard is on a steep incline with lots of existing stone retaining walls/steps and plants.

I am due to have a visit from a Landscaper however I am keen to hear opinions from people on this forum on whether it is even feasible to improve this for a duplex site. I am quite concerned on the amount of work and the difficulty of the work required.

Thanks in advance.

 

Scary cost for that. Retaining walls are costly and height multiples cost.
Why not a dual level yard ? May also assist with noise etc. Depends on width and council for side / rear access. A Town Planner may assist with designing use of the land to comply.

 

If you haven't started designing the duplex then tackling both issues at once may greatly assist.

Things like having an undercroft garage and raising therefore the floor level of the house would have a great impact.
Creating a split level design with even 4-6 steps between the levels will mean 1m that you don't need to retain at the back

Depending on how far/long the duplex is and how you design it will impact what amount of space is left at the area.

 

It may help if you give the sqm's and how far the block goes back ,i can scale the levels out from the back door and the number of x face bricks but unless some can see how far that block is from the back door it would be very hard to give a opinion..imho..

 

Have you considered a split level?

 

Yes I am afraid of this but it depends on the cost I suppose. I am hoping to just split the yard down the middle atleast and hoping to repair/replace the existing retaining walls.

Nope haven't started designing the duplex. It will be a knockdown rebuild most likely and yes in fact it will have an under garage (3 storied at the front and 2 storied at the back)

I have uploaded a site plan with the existing house. Yard is approximately 15m x 18m. I appreciate the help.

Thank you everyone, appreciate all the responses.

 

Until you've started house design and tried to take in as much of the slope with the house design this is practically impossible to answer.

Design ideas
- make garage 3000mm tall instead of 2550 so that the finished floor level of the ground floor is half a metre higher and you then don't have to retain that amount in the garden area
- if the top floor only sits on the front half of the middle/ground floor then consider stepping up the remaining part of the ground floor to further increase the height where it joins the garden area
- slope the driveway up and start the garage floor level 500mm higher than street level

For every mm you can increase through the front setback, garage, ground floor the less you will need to terrace and retain at the rear

You will need terraces of some sort at the rear and yes starting again will help to make it more useable.

@Leo2413 did a duplex with a large slope at the rear. I can't find the thread now but he might be able to come in and give some tips on the engineering things he learnt trying to tame the slope

 

Hi Westminster, that's okay your suggestions are more than helpful already, don't need the correct answer at this point. Your feedback gives me good questions to ask when I approach the design phase. Thank you so much.

 

@Westminster we are actually starting that build this year, put it on hold to complete first a jv commercial dev at the time. It's actually 2 free standing homes. But yes its a split level design into the slope of the land. 2 slabs with a small retaining wall at the back. I think split level designed into the slopage of the land will be the most cost effective .

I got my engineer to work closely with the builder on that one while we were designing it.

 

Thanks for sharing