Cutting paving slabs for damp course

[petemc]

Happy New Year everyone

We were recently told that our back yard is too high and it's caused the damp course to fail. It's been suggested that we dig a trench around the house about 2 bricks high and then redo the damp course.

We were told that we could save a fortune by doing it ourselves. The damp course injection part sounds easy enough. Drill n fill. The problem we have is were to start on creating the trench.

My girlfriend and I aren't diy types and fully expect to lose limbs while creating the trench. Is it an easy thing to do? Do I just buy an angle grinder, cut off some space and then dig a trench?

I suppose by the time I've read up on it all and spent days doing it a professional could have done it in an afternoon or something. Is it a big job and worth getting someone in or something I should man up and do myself?

Thanks

 

[RedHerring2]

Have a read of this first:

//www.diynot.com/forums/general-discussion/chain-saws.305657/

Yes, it's easy enough, if you're familair with the tools and techniques.

Yes, you could hire an angle grinder, you'll probably need a 9", if you have 40 -50 mm thick slabs. This is a dangerous tool in the wrong hands. If you're not confident, get someone else to do it.

Digging the trench is easy enough. I can't see you getting into any trouble there.

I'd lift the slab completely, dig a wider trench to give yourself working room.

Even if you do this much you'll save yourself a chunk of cash.

You'll need to install some barrier to prevent the soil going up to the wall again, perhaps a layer of bricks. Relay the cut slabs and make good.

 

[petemc]

Hmm easy enough if I'm familiar with the tools. So not easy then

I'm a photographer. The last time I used any real tools was probably 17 years ago in school under the supervision of an adult. I'd have to hire an adult to supervise me

A man has died in front of his wife and daughter after accidentally cutting his throat with a chainsaw.

That's me sold

 

[RedHerring2]

Don't be too put off. It's probably only cutting the slabs that you'll need to use a tool that could cause serious harm if it goes awry.
A 9" angle grinder with a cutting disc has a lot of torque, when you start it up, you'll feel it and if it binds and kicks back, you may not feel it, if you get my drift.

But knowing how to use it properly, if it kicks back it should kick away from you. If you're steady and stable on your feet, there should be no danger. If it's below knee height, there's little danger of life-threatening injuries.
Ensure there's no one in front of you!

And wear the PPE.

 

[r896neo]

We were recently told that our back yard is too high and it's caused the damp course to fail. It's been suggested that we dig a trench around the house about 2 bricks high and then redo the damp course.

What age is your house? Unless its very old you shouldn't need to redo the damp proof course if there is a physical one in place and you've lowered the ground?

The grinder is a bit dangerous but there is an easy remedy, just hire a stihl saw as this has a clutch which will stop the blade should it bind into something.

Your one problem with a stihl saw will be getting near the wall, but as long as your right handed you'll have no trouble cutting 4-6 inches away from it which is probably what your after.

You could just fill the trench with clean gravel once its done.

 

[imamartian]

I'm a DIYer, and i own a 9" anglegrider, and i quite often use a stihl saw...

There is a knack, and it helps if you're quite strong, and know how to get balanced on your feet.

I find it better to go slowly, and cut less each pass.... it's a bit like eating hot soup, take small amounts and you'll be ok, but if you stick your spoon right in and down the lot, you'll get burnt !!

PS if you're really not sure, for a few quid get someone in, don't take unnecessary risks !!
Good luck.

 

[petemc]

What age is your house? Unless its very old you shouldn't need to redo the damp proof course if there is a physical one in place and you've lowered the ground?

It's old enough and due to some stupid design choice the back yard is at the same height as the indoor floors. It's a long story but we recently had some flood damage work repaired and this exposed the damp issue we have.

I'm looking to get Peter Cox in Liverpool to do a free survey and start us off on what needs to be done. The trench and new doc was advised by our plumber recently.

 

[r896neo]

What age is the house?

Its more a case of years of tenants re-paving with what they think looks nice but can;t be bother to dig it out and do it right, rather than bad design.

I don't know who peter cox is but i would be very wary of a 'surveyor' who also sells damp solutions for a living.

 

[petemc]

House is from the 1890's.

The decorator from construction company who sorted our floor damage recommended Pete Cox. They said "Ring these guys up and get a free quote. It's completely free and that will tell you what needs doing. Then go off and do it yourself." Hence me being here today

I don't know them from Adam Cox but it's free and something to do.

 

[r896neo]

I understand its free but You are presuming his advice is impartial which it is not. Whilst you may go off and do xyz that he recommends yourself his advice in the first place may be flawed and you end up doing unneccesary works.

Just be sure to take it with a pinch of salt.

 

[petemc]

Yeah I appreciate that which is why I'm here trying to get advice as well.

 

[JohnD]

a house that old might or might not have a damp course. Have a look at the front of the house, or a similar neighbouring house. You will be looking for a thick mortar joint, preferably about two courses above ground level, with two horizontal layers of black or grey slate embedded in it.

Slate docs last for ever, unless they are bridged, or broken by the wall cracking.

I agree with the idea of taking up the first row of slabs completely, it will give you more room to work.

 

[petemc]

It's definitely had dpc done. You can see the holes in the brick work where they've drilled in and filled. We know its been done and we know its failed. What we need to know is how to fix it Whether we can ourselves or how much it'll cost to get someone in.

 

[JohnD]

digging the trench is the better thing to do. Injecting more silicone you can put aside until the trench has been done.

Have the ground floors have been relaid as concrete? If they are still wooden floors and the airbricks have been buried it is very liable to damp and rot.

 

[r896neo]

how do you know the dpc has failed and has not simply been bridged?

As john says do the trench first and see what happens