It's a rental house...

2 yrs ago, the place was filled with grasses... I ask professional to cement it and bcome house car park... Now, those cement crack here & there. Big & small holes... Grass grow back too.

How to DIY CEMENT IT? THE MIXTURE OF CEMENT Sibce it need to park car /heavy loaded.

This post has been edited by hotguuy: Feb 2 2021, 01:21 AM

The loading is actually just two lines (where the tyre rolls), which cause the cement to crack as its unevenly loaded (the car is not the same as a box).
So the crack repair should be slightly elastic (not rock solid).

If the slab was made into few sections (with small gap in between) it is less prone to cracking than the full-driveway size.

Crack repair if its quite big like hotdog size use sika grout
or if its just chopstick size small crack can use Sikadur crack seal

If proper base prep (underlay with gravel stones) before pouring concrete then it should be less prone to cracking. However the best concrete also cannot tahan if neighbour house got a mango tree with roots growing everywhere.

This post has been edited by ceo684: Feb 2 2021, 02:21 AM

U sounds pro. Especially u mentioned slab made into few sections.. But, I don't my current got any joint. (still able to do it?)

The crack not small.... Maybe like our hand size, chip off here and there..

This post has been edited by hotguuy: Feb 2 2021, 03:20 AM

A RC (reinforced concrete) slab of specific thk on the ground must be casted on top of compacted crusher run of specific thk (for new house less than 10 years) and laid with BRC (A7 or A8). Concrete provides good compressive strength and steel on the other hand provides excellent tensile strength. This combination will prevent concrete slab failure.

A RC slabs with multiple cracks that divide your ground slab into various segments indicates structural failure may due to missing or insufficient BRC, missing crusher run as base, insufficient thk of RC slab or etc.

This is not your usual micro cracks (less than 2mm) that appears at a joint area that can be resolved by mere DIY products. It must be demolished, temporary removed (reuse in the event of a missing crusher run layer at specific thickness and must be compacted), RC will be recast with BRC and cement rendered as finishing.

Reminder: A crack width that comes in a size of our palm is no longer a crack, it is known as a broken slab. The RC slab has failed.

But, the crack is not deep...

1. Dig the area 100mm extra + desired slab thickness, 150mm?
2. Compact the sub-base.
3. Lay PE sheet/plastic sheet.
4. Lay 100mm of crusher run.
5. Compact the crusher run again.
6. Lay single layer of brc A6/A7 with spacer.
7. Pour concrete + floor hardener mix.
8. Broom finish for better tyre grip.
9. Grinder cut a line between existing flooring and fill with sikaflex.

The slab should last awhile.