Will concrete hold on this slope?

40701085

Afternoon folks,

Planning on laying some concrete upto the garage door at home, the problem is the garage door is higher than the driveway by 7-8 inches. There is gravel there already rising up to about 4inches below the threshold. From where I want the concrete to start, there will be a gradient of approx 8%.

I'm ordering readymix, my question is will it be too "soft" to hold the slope? Can I order it a little drier so it will set on that slope, or how could I get it to hold?

Thanks for any suggestions

bugsntinas

I'd imagine when you order it tell them about the slope and they'll deliver it drier as the driver will always wet it down if necessary.

deandean

Yea I had that situation a few years back, I asked Mr Beades to deliver the conc fairly dry, the driver would dump a slop of conc, 'this ok?', add water, dump a slop 'this OK?', etc until the mix was just right.

Now I had a concrete-meister with me who knew when the mix was AOK. And that, sir, was the secret! Best of luck.

GY A1

do you mean 8 degrees,
try and order the concrete mix at the right slump from the start as the more water you add on site, you are weakening the concrete :eek:

sonofsteptoe

Ask for 30 n 20 with 50mm slump, That'll hold no bother

40701085

Thanks all, thats good to know, was just onto the rep & they'll bring it out dry & add the water as needed from there on, like you say.

Final thought - would I need to put some rebar in there for 4inches depth? Not a lot going to be travelling over it besides the family car. I was thinking if I got some handy somewhere, I'd throw it in, but not sure if its vital...?

Now just need the frost to clear

deandean

Well, following some good advice I put steel into mine. I was told it would stop cracking and indeed there is not one crack after 4 years.

Here's what I did: I got the steel grid, the light stuff, think it's 5 or 6mm bar, comes in sheets about 12' by 6', builders providers will deliver it to you. Get enough to cover the entire area. Use a bolt cutter or angle grinder to cut to size. No need to go wiring the bits together.

Pour the concrete, roughly level it out with the board, place the steel on top and walk the steel into the concrete so it's 20mm or so down.

Then do your final level and smoothing, etc.

This way the steel is close to the top of the concrete which is where you want it to stop cracking.

Best of luck. Remember to have a few mates on hand, you gotta work fast in the early stages.

Also: it's important to have the 804 base well compacted, using a vibro plate or even better, a roller - especially if the odd truck will be driving in.

Dean

[edit] 300th post!!! I must get a life.

jack of all

Just my tuppence worth (20 years experience in construction) rebar is certainly no harm but it ideally needs to be near the bottom of the concrete pour- concrete is good in compression, no good in tension and this is why rebar is needed at the bottom of the pour. Prop your mesh up on broken bricks or small offcuts of paving slab, ensuring a minimum of 50mm concrete cover to the steel to prevent corrosion. When planning the gradient/ overall run of slope remember to ensure a safety factor so as not to take out the sump on your car's engine or the back box, if the slope is too aggressive! It's also a good idea to include a drainage channel (aco drain or similar) at the existing threshold and concrete this in, ensures that any water/ snow etc which does run down your door is diverted away and won't run under your door. might add €150 to the cost of the job but worth it in my view- belt and braces job!

40701085

Yep, have a space left for a drainage channel, better to have it in there as you say. For the same reason, will look for some steel to put in now based on all the comments.

Cheers!