Sunken areas in lawn

GALWAYGIRL27

Hi all.

We have about 6 or 7 sinking areas in the front lawn. We built the house 11 years ago and reseeded and levelled the lawn 8 years ago. The first sunken area started to appear about 7 years ago and the rest about 2 or 3 years ago. The first one is quite large now and they all look the same as the first one did when it started to appear. Photos attached. There is a bored well in the front lawn too and the landscapers took some rocks from the field when levelling it. The soil is very soft and boggy. The back lawn is fine. The front lawn slopes downwards also towards the road. We are in Galway. Has anyone any ideas on this or seen this before. Thanks in advance.

20240226_114754.jpg

20240226_114729.jpg

20240226_114713.jpg

20240226_114551.jpg

20240226_114545.jpg

20240226_114637.jpg

Jim_Hodge

It may be as simple a fix as filling any dips with topsoil/compost and reseeding.

MacDanger

Would there have been bushes or anything buried there after construction and these are now decaying and creating a void into which the soil overhead is collapsing into?

Maybe less likely but do you live in a limestone/karst area where there might be underground water channels in the rock that could be eroding away?

GALWAYGIRL27

We don't live too far away from the Burren. If this is the case what would we do please? Thank you.

MacDanger

As Jim said, just fill the hollows in with topsoil and reseed

Seve OB

Sand may be your friend

GALWAYGIRL27

OK perfect. But what if it keeps sinking?

GALWAYGIRL27

Thank you. What type of sand specifically and how does it help? Excuse my ignorance on the situation.

GALWAYGIRL27

Could we fill with stones and cover with topsoil and reseed?

MacDanger

https://www.boards.ie/discussion/comment/121819456#Comment_121819456

There's probably not a lot you can do if it keeps sinking - either let it sink or backfill it are your options I'd say

Yeah, if it's deep enough, you could fill itwith stones and then cover with topsoil

looksee

I'm not sure how the sand would help in hollows as big as those. You might consider taking the sod off one of the areas and investigating a bit so see what is happening. If it is something like tree roots that have rotted away then filling with stones and sub soil might be the way to go, then several inches of top soil. If you take off the sods you could replace them on top of the in-fill, probably add a bit more topsoil and re-seed..

Seve OB

https://www.boards.ie/discussion/comment/121819467#Comment_121819467

sports sand is the best, but really any kind of sand would do

its easier to level off than soil IMO and will help your soil for drainage especially if its soggy and quite clay like

you can also get mixes specifically for this kind of thing

depends on how much you need also comes in tonne bags or maybe you need more and a lorry load would be better value

Seve OB

https://www.boards.ie/discussion/comment/121819476#Comment_121819476

dig out a big hole or trenches

line it with weed control fabric

fill it with small stones(pebble), use some drainage pipe also if you can

cover the stones with the fabric

stick about a foot of topsoil across the top... it will probably sink a little as it settles over a few months, but not much. lash a bit of sand over and level the gaps off next year

GALWAYGIRL27

Thank you, I'm paranoid they are sinkholes about to open up 🤯

Seve OB

https://summerhilllawns.ie/product/rootzone-sand-and-peat-mix/

option

autumnalcore

I know this is an old post. Do you know where your soakaway and drainfileds are? Bigger area could be soakaway. I lived in karst area for 10 years and subsidence is basically inevitable, rain and water from soakaway/drainfileds gradually washes material away down the grykes. Heavy geotextile helps if you have a friendly neighbour with a backhoe https://www.mdpi.com/2076-3417/11/24/11826