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View Full Version : I need advice from a builder..Concrete



RobbieT
31.03.2015, 07:16 PM
So back in the 2010 winter snow my Conservatory basically caved in and I managed to get a new one rebuilt going through the house Insurance.
The house ground & conservatory floor is higher than my back garden so it had a large step/concrete slab raised on bricks with another concrete ramp going down to the garden level.
10348

After the New Conservatory was built I noticed the large concrete slab at the door was cracked clean in two and wobbled excessively. I suspect it was due to poor foundations under the slab which then when the weight of the old conservatory was removed allowed pressure to crack it by the weight of the men & materials walking over it building the new conservatory. This was obviously not evident when the old conservatory was demolished, and was not part of the contract for the company to rebuild along with the new conservatory, but when I pointed out this to them they agreed to rfix and re-concrete the platform as a gesture of goodwill.

They actuall made a pretty good job of it, visually, and structurally, or so I thought....
All was fine until after this winter I notice a gravelly texture under foot. Initially I thought it was the leftover salt & grit after the Ice, but upon closer inspection it appears the concrete surface of the platform is now disintegrating....

...help...what do I do now????

:thumbs

bluehawk
31.03.2015, 09:47 PM
Robbie,

Is it just the top of slab that is loose? Frost usually breaks the surface of the concrete up and it might not get any worse than the surface laitence breaks up and leaves a slightly rough top.

There are a few things you can do..

Have the slab ground back to a firm base again it can be done with a diamond grinder or carborundum ( but there's a chance the same thing happens again if the concrete isn't particularly strong.)

Seal the slab with a resin coating or screed.

Seal it with a normal coating or floor paint (tends not to last too long).

Show us some pictures of the slab up close and might be able to make a better assessment.

All the best

G

RobbieT
31.03.2015, 09:57 PM
Robbie,

Is it just the top of slab that is loose? Frost usually breaks the surface of the concrete up and it might not get any worse than the surface laitence breaks up and leaves a slightly rough top.

There are a few things you can do..

Have the slab ground back to a firm base again it can be done with a diamond grinder or carborundum ( but there's a chance the same thing happens again if the concrete isn't particularly strong.)

Seal the slab with a resin coating or screed.

Seal it with a normal coating or floor paint (tends not to last too long).

Show us some pictures of the slab up close and might be able to make a better assessment.

All the best

G

Thanks mate,

It seems to be just the surface of that new slab so I suspected it perhaps should have had a coating as the old surface was never bothered after winter and all of the other older concrete surfaces are undamaged since winter.... So Defo something about the new concrete composition or finish !!!!

I will take some pics when the weather improves and post up.

Many thanks for advice/help!

:thumbs:

bluehawk
31.03.2015, 10:11 PM
When was it done Robbie? Was it cold at the time it was poured and was it mixed by hand or come in premixed?

Concrete gets harder the older it gets.

Makes typically about 40nm in normal form. Resin screed does about 80nm.

hindsight
01.04.2015, 06:55 PM
I had something similar with the floor of my workshed when I first moved into my current house, the surface was degrading. I applied an epoxy floorpaint a few months later, and it has been fine for the last four/five years. I'm sure Gareth (bluehawk) will put you on the right track though - he sorted a surface problem in my main garage last year.

mike

RobbieT
06.04.2015, 09:01 PM
Thanks Guys,

it was done back in 2011...Jan or Feb I think, didnt see the work bineg carried out as I was at work when it was done.

It feels like walking on fine loose gravel in the middle bit but the edges seem to be fine...no damage.

Photos=
https://farm8.staticflickr.com/7659/16870460418_c01f7352f1_z.jpg (https://flic.kr/p/rGMw8d)

https://farm9.staticflickr.com/8764/16870717030_be63fc9548_z.jpg (https://flic.kr/p/rGNQpy)

https://farm9.staticflickr.com/8818/16850852677_67a6a726aa_z.jpg (https://flic.kr/p/rF42qH)

https://farm9.staticflickr.com/8765/16438108203_9228e44841_z.jpg (https://flic.kr/p/r3zASF)

:thumbs:

Andrew H
06.04.2015, 09:31 PM
I bet that crow has been pecking at your concrete - he's really got it in for you :eek:

bluehawk
06.04.2015, 09:54 PM
Robbie, doesn't look too deadly. I'd be tempted just to scuff the top with a diamond cup disc and seal it.. You could throw a bag of kiln dried sand into the top while its wet and have a hard wearing and durable finish. Atb. G

RobbieT
07.04.2015, 08:50 PM
Robbie, doesn't look too deadly. I'd be tempted just to scuff the top with a diamond cup disc and seal it.. You could throw a bag of kiln dried sand into the top while its wet and have a hard wearing and durable finish. Atb. G

Thanks,
I will look into getting the stuff then this week and see how much of it I can handle myself!
Not exactly known for my DIY skills.
Will update on any progress!

:thumbs:

bluehawk
07.04.2015, 10:11 PM
Robbie,
You might struggle to get something up that would be durable outdoors, try NCC Bathgate for a coating, might cost a little more, but worth it in the long run. He can give you the correct aggregate for casting into it too.. I can talk you through it if you want. Atb. G