[Ice]

I have to repair a smallish hole in my concrete floor.  I have sharp sand, cement, a wheelbarrow, shovel and a hatred of unreliable builders.  Hence my decision to do it myself.

What ratio sand to concrete should I use, how wet does the mix need to be and how do I get it level? 

Next week I will be asking how to plaster a wall.

[ANHBUC]

Not sure of the mix but a tip to make it adhere to the existing concrete is to mix PVA glue with water and brush it on the repair area.  Let it dry and then fill with your concrete mix.  This is used when rendering walls as well so might be useful to know.

To get it level use a large piece of wood say 2 1/2" x 4" and about 10" longer than the widest part of the hole.  When you have put enough mix in the hole use the wood to tamper the wet concrete down using the 2 1/2" side on the concrete and working from one end to the other.  Excess should be forced to one end and out of the hole, or add more mix if the level falls below the existing concrete and repeat tampering.  Hopes this makes sense.

[Ice]

Good idea to use PVA as I might raise the entire floor level as well as fill the hole.  It's only the floor in a coal barn which I've had converted into a pantry.

Pretty sure the ratio is 5:1 sand to cement.

[ANHBUC]

Need aggregate in concrete though not just sand and cement as that is mortar.  Here is a link with some help for you.

www.diydoctor.org.uk/projects/mixing_concrete.htm

[mumofstig]

from Diynot

Before beginning, repair any cracks deeper than about 3mm (1/8 inches) by cleaning the cracks and removing any loose debris - with a hammer and chisel if necessary. Apply PVA adhesive and then fill the cracks with a sand and cement mortar using a 3/1 mix.

[Ice]

Thanks mum, rest assured I will have the cleanest crack in the village.

Looks like another trip to Wickes for gravel.

[mumofstig]

Thanks mum, rest assured I will have the cleanest crack in the village.

Looks like another trip to Wickes for gravel.

careful when you put gravel in it then, sand is rough enough IMO 

[aelf]

Chisel out the loose bits around the crack (wear safety goggles!) remove all the loose stuff. I mix it 3:1:1, sand:gravel:cement to a stiff mix. Wet the sides of the crack a little (I use a spray mister), it helps the mix to stick. Trowel the mix in and flatten down. Wet the surface of the repair with a little water and smooth it with the trowel.

Job done! 

[RichardA]

if it is a small hole then gravel not needed IMHO, use sharp sand and cement about 3 to 1, mix to stiff rather than runny condition, ram down well into very clean and well pva'd hole, if possible key hole the crack etc so repair mix has something to bind to. (like a dovetailed slot) keep damp after it has hardened for about 7 days to reduce skrinkage, but do not get too wet. There are many repair compounds around that already have PVA or similiar in them. Self levelling and topping compounds also available
Would have helped it we knew what "small" meant.
Best of luck
R

[Ice]

The old coal barn is 3'x4' approx and one end is damaged from years of tipping bags of coal onto it, about 18" diameter.  However, I am now going for the big one and not only fixing the hole but raise the entire floor level to match the kitchen floor and then self levelling compound followed by matching tiles.  If it works I will reward myself with a very cold bottle of Old Peculiar.

Thanks all.

[RichardA]

please let me know when the job is done as I feel duty bound to celebrate with you, I am working up a thirst jsut listening to your plans. The very best of luck..
R

[Paul Plots]

Best of luck Ice.... I know you can do it as I managed something similar... (I'm normally only around piles of books) 

[hillfooter]

Need aggregate in concrete though not just sand and cement as that is mortar.  Here is a link with some help for you.

www.diydoctor.org.uk/projects/mixing_concrete.htm

Just what I was about to say.  Particularly if the concrete floor is outside in an outhouse and it's not just a crack repair you will need some aggregate.  If it's just a shallow crack, a heavy sharp sand will do(river sand) is best.  In your area the sharp sand usually available can be fairly fine so try to get a coarser grade.  You will need a cold chissel and a cloub hammer or you can hire a power breaker to enlarge the hole for better keying and removing loose old concrete or better still, hire a JCB with a bucket digger and start again.   Pop round to me afterwards and repair my drive.  

Have you thought about starting a building business as these jobs tend to snowball?
HF

[Ice]

[Have you thought about starting a building business as these jobs tend to snowball?
HF

That's just what I was thinking when I read your post.

It's a four foot by three foot pantry which used to be the coal barn.  I doubt very much that it would be possible to get a JCB digger in the kitchen, but will try.

[Lardman]

If you have a been and queued locally they sell premixed bag of aggregate (sand/gravel), just get a couple of bag of that and a bag of cement.

I don't see any mention of a damp proof course.
 
edit ... "All In Ballast Natural Large bag" should be 1.64