Retaining wall collapse - Needs advice on type of drainage

[Den81]

Hello Everyone

We recently tiered our back garden. The ground level was retained with 6" block. The wall is about 6' 4" high - 30feet wide.
My husband hadn't put any drainage in or behind the wall and after some heavy rain.... the whole lot came tumbling down !!

He is having another go at rebuilding the wall... he's put some very small Beak Weeps in at 1 metre gaps. I'm worried that these tiny little things won't be enough. The garden goes up approx 70 feet.

Can anyone please tell me if there is something we need to put BEHIND the wall to help it drain away??

Thanks
Den

[rab1]

this is on for pros, but you will have to put some kind of drainage behind the wall. :O

[lutonlagerlout]

hi
there is some good info here
but for a wall that high you need to have it designed by a structural engineer
i built this one to a design but the foundation was 300mm deep by 1000mm wide all reinforced with rebar


the steel goes up the inside of all of those blocks and is then concreted in place
plus there is a land drain encased in pea shingle at the back of the wall
you really need an engineer before someone gets hurt
LLL

[mickg]

Den building a wall over 6 feet high without any structural engineering details is certainly not a DIY job and someone could of been injured when the wall collapsed

we can't give any detailed advise on what to do as we could be held liable for the advice given if anything happened, I hope you understand

[seanandruby]

Tell your husband to leave it to the experts.
The risk of a serious accident, and somebody getting killed there is very high. The wall really needs to be anchored to the foundations with reinforcing rebar. This is an highly skilled project that needs the advise of a structural engineer. Sorry i can't help, for reasons stated in above posts

[flowjoe]

Thought anything over 1200 needed design by structural engineer ?.

Talking to a guy this week (3rd generation construction company) where HSE turned up on site and insisted on a design on a 600mm retaining wall.

The end is nigh

[lutonlagerlout]

I know you need railings on anything above a 600mm drop
thing is when walls go,people can die
LLL

[seanandruby]

Den i hope you persuade your husband to take our advice.
A photo of the ruin would be nice, also one on completion.

[Den81]

Thank you so much everyone for your advice. I've persuaded my husband to put some drainage behind the wall (as well as the Beak Weeps he's already put in).

He's going to put some steel columns in at regular intervals also. He's a stubborn git who hates being given advice! He's spoken to people on the site he's working on who gave him a bit of advice (he's a plasterer).

How do I add a photo to my message so I can show you the before and after? I just clicked on IMAGE but it says something about an URL ?????

Cheers
Den

[seanandruby]

here
Being stubborn can cost lives tell him

[mickg]

you need to upload the photo's to some web storage which you then paste this URL into the box you mentioned, if you can't sort it out email me the photos and I will resize them as required by the forum and upload them for you

[Den81]

Mickg...... what's your email address please? I'll send them to you if you don't mind.... the webspace..URL thingy is all a bit too much for me. LOL

[Den81]

Would you advise a land drain that has perforations all round, or just on one side (I presume this one would be laid with the hole facing downwards?).

Thanks.
Den

[seanandruby]

You will need to connect to an outlet of some sort. I would lay the holes uppermost to carry the excess water away. Also you need to incorporate good size weep holes at base of wall.

[Den81]

Thanks Sean

I've convinced the husband to lay land drain and we (I) am in the process of ordering it...... after several heated debates (arguments) he's accepted he doesn't know everything LOL !!

I'll post some pics via Mick soon.

Thanks everyone.

Denise x