The Garden Community for Garden Lovers

Hampshire, United Kingdom Gb

We have a garden that slopes away from the house down over 4 levels. In the past a previous owner has BADLY built a retaining wall made of breeze blocks but they failed to put in any poles through the blocks and so the wall is now cracking with the weight that it is holding. The wall is approx 8' high and approx 15' long and we would love to hear some ideas on how we can remedy this problem. We had some iron corner brackets made to support the corner of the wall for a period of time whilst we decided what would be for the best. The level above is grass and flowerbeds and the level below is grass, but a smaller level overall. If we just leave it we fear that we will wake up one day to find our top level collapsed onto the lower level. Any ideas would be welcomed. We don't have a lot of funds so if anyone can give us ball park figures on possible costings so that we know how much we would need to save up - that would also be great. Thanking you all in advance for any advice you may have.



Frankly, I think the best advice I can give is that you get a couple of builders and a couple of landscapers to come round and give you estimates - get 4 if you can, 3 will do otherwise, then at least you'll know what kind of spend you will need to make to put this right. Sounds to me like a proper retaining wall needs building, preferably with some footings.

6 May, 2010


Sadly agree with Bamboo - not something to tackle yourself!

6 May, 2010


Ive read this a few times to make sure details are correct you have an eight foot retaining wall built with breeze blocks that are showing signs of cracking ?

I do not wish to be alarmist but this is is quite serious as many tons of soil will be behind this and the sheer height of this would require a substantial double skinned wall with buttresses drainage channels etc .

The previous owner should have divided this area to create another level with 2 x 4 ft walls rather than one large 8 ft one.If cracks are appearing through the blocks rather than along mortar joints then this indicates subsidence.

Either way it is clearly not up to the job and could prove dangerous.

Bamboo and MG are quite right and unfortunately this needs to be done professionally as its been done cheaply and sadly you have inherited the consequences.

It really would be inappropriate to give diy advice as there are safety issues to consider.I would suggest consulting a structural engineer they aren t cheap but will advise you how to proceed the cost of works and should leave details for any builders to follow.

I m sorry but any works will not be low cost as either you ll need a substantial wall or another level created to reduce the height of this. This would involve further earth removal creation of more steps etc.

I fully appreciate your concerns for cost implications but how much would it cost to clear if wall collapsed and heaven forbid anyone was close to it should that happen.

7 May, 2010


Thank you all for responding to my query. The REALLY annoying part about this is that we did get builders to look at the wall before we purchased the property and they each told us that it looked solid and was not an issue but that if we wanted to avoid it collapsing then we should build a further wall in front of the old one and this time put proper footings in!! If we did that, surely when the existing wall collapses it would simply knock the new one down with it??? The old wall has been built with drainage points but they are low down and most of the moisture in the soil would have drained off well before it got that far down! The wall was built approx 6 years ago from what we can make out and was put up over a weekend!!!! We are open to ideas to alter it into 2 smaller levels but don't know what the most cost effective way of building retaining walls is - anyone built retaining walls in their own gardens?? Thanks again.

7 May, 2010


My advice remains the same - get a landscaper or builder or both to give you their ideas and costs to put it all right - and make sure they're quoting for the same work -very often, quotes look cheaper because they're not doing the same thing. Even if you don't use the people who quote and do it yourselves, you'd at least know where you stand in terms of how serious and difficult the job will be, not to mention the costs of materials, which will be a fair portion of the overall costs anyway.

8 May, 2010


I work as a gardener my brother is a builder having done the groundwork for terracing and dug footing channels ( the jobs builders hate ) for walls I can certainly testify to the amount of soil that requires moving.

Many people undertake terracing assuming its a simple question of moving soil from one level to the next and levelling off you ve brought the section you ve cut out down and need to cut another one .Increase this by the number of levels and you are left with tens of tons of soil - and other rubbish you ve excavated.

The simplest way of seeing this is to draw a diagonal line then a line of steps below it for each terrace like a flight of stairs each of the steps needs cutting out and as you come down the steps your bringing the previous soil - and the one that needs cutting out - with you , look what happens at the bottom !

This probably explains the construction of such an unnecessarily high wall a simple? solution to disposing of the tons of soil etc .

You seem to be determined to attempt some work to reduce cost implications all advice being given is based on what you have to deal with and some of the potential problems you will encounter .The sheer tonnage of soil and whatever else has been buried behind this wall could easily exceed 20 tons and by creating another level - which should have been done originally - you could be looking at removing 10 tons plus .Where to ?

By pulling this down a level you simply create similar problems further down the terrace - it needs removal.

If you have never tackled anything like this then sure it is hard to imagine the volume and weight behind that wall when wet this is hugely multiplied.

Sorry your reply seems to suggest there must be a simple way of creating retaining walls .Yes there is but they do not address the problem you ve inherited.Even 4 ft walls require serious construction esp if they involve steps and form the entrance to your home.There is more to consider than a high retaining wall holding back a raised flower bed for example.You seem to be confusing the two.Its why I suggested independent advice as this will be given based on needs of the work and not on needs of tradesmen or perhaps your failure to realise the stresses such walls are placed under.

I am no builder but feel experienced enough to warn you of the serious amount of soil etc that needs shifting.Its heavy duty stuff and concerned that your enthusiasm and need to minimize costs is over riding the implications of the work involved.

You must ve seen those Diy programmes whereby homeowners are unable to complete jobs as work involved becomes too much for them .They end up wasting time and money using inappropriate materials and tradesmen often charge more for having to undo things to put them right ..viewed from this perspective such advice is actually saving you money.

I have only gone to trouble of further reply because I know the amount of work involved.

I suspect this is not what you wish to hear but If after all this you still feel able to tackle it then at least I can sleep at night knowing you had been warned .Good luck.

9 May, 2010


Thanks, sorry if my previous comments led you to believe that we planned on tackling this ourselves - we realised that this is a major job and were simply looking for ideas on best way to remedy this - ie build a stronger more substantial wall in front of the existing one, as per a builders suggestion, or to remove this wall and a large portion of the soil and allow it to return to being a sloped garden, or to remove the wall, remove a large part of the soil and replace with two smaller walls, thereby making two levels where there once was only 1. Also to get advice on best materials for making retaining walls and, if anyone was a builder, to give a rough ball park figure to allow for work - ie thousands or tens of thousands?? lol
Thank you for your concern, we do realise that we have a major headache on our hands that needs planning for its proper removal/replacement.
Kind regards - Caroline

9 May, 2010

How do I say thanks?

Answer question


Previous question

« how to take cuttings from a cotoneaster


Not found an answer?