Sand wash pricing?

[Baht Man]

Anyone have a rough idea of the cost of "sand wash" or "exposed aggregate" cement covering.
I've seen it around on houses and often used on swimming pool decks.

Thanks

[Geoffrey]

Payom Pan Mai near Rangsina Bus Stop has exposed aggregate paving slabs. 45 cm x 45 cm

[Baht Man]

I need the overlay on existing concrete, not the slabs.
But thanks anyway

[fatbob]

Its about 300 baht a square metre materials and labour.

[fdimike]

It would be a really good idea to consider using a bonding agent as well since new concrete doesn't really adhere very well to existing concrete. The typical Thai solution is to wet down the existing concrete before applying the sand wash. This works well for a short time but then the new concrete will pull away from the existing concrete as it cures leaving a void which will be suceptible to cracking. There are a number of bonding agents available in every home center here in UT.

[fatbob]

The best bond is to completely scabble the surface of the old concrete you are trying to adhere to.

[fdimike]

Sorry to disagree with you but new concrete does not normally possess much of an ability to bond to old concrete even if you "scabble" the surface. A bonding agent takes the guesswork out of trying to get new concrete to bond to old concrete. On top of it all it's relatively inexpensive, very easy to use, available in all the home centers around UT. Normally all you do is mix a specific amount with the new concrete in place of some of the water. Normally the instructions are in both English and Thai.

[fatbob]

Do it your way then, I certainly won't.

[Baht Man]

Its about 300 baht a square metre materials and labour.

I've gotten 400 to 450 PSM from three local sources

[Baht Man]

The best bond is to completely scabble the surface of the old concrete you are trying to adhere to.

Define "scabble" please..

[Baht Man]

Sorry to disagree with you but new concrete does not normally possess much of an ability to bond to old concrete even if you "scabble" the surface. A bonding agent takes the guesswork out of trying to get new concrete to bond to old concrete. On top of it all it's relatively inexpensive, very easy to use, available in all the home centers around UT.

Like where, I mean what does it look like,, paint, powder, can, bag?

I have no idea what to look for.

Thanks

[fdimike]

Baht

It's normally a liquid which is mixed with the new mortar or painted on to the old concrete (depending on the brand and instructions). TOA has a product called "Super Bond" and it's normally in the paint section. There are a numnber of other brands as well but the names are normally in English and have something to do with BONDING. The instructions are written in Thai and English on several brands. The stuff looks a lot like "white glue". This stuff is available in every home center here in town to include I believe the newest ones. Another good company is Lanko.

When in Global House and facing the paint aisles from the center aisle this stuff should be to your right. You'll also see concrete waterproofing addidtive and the like in this same aisle.

[fatbob]

coxo wrote:
The best bond is to completely scabble the surface of the old concrete you are trying to adhere to.


Define "scabble" please..

I will post a photo tomorrow, basically you rough the surface with a scabbling hammer, electric or air or a fine point with a jack hammer, you rough up the surface to create a keyed bond between two surfaces, once scabbling is completed you then pressure clean the surface before applying topping concrete, standard procedure for large construction companys, bondcrete can then be applied for additional bonding if you want to do the ultimate job, most do not, bondcrete is a PVA based product.

[maaka]

I must admit, in all my former years as a builders labourer barrowing and laying concrete for several city reservoir's, Mall's, factories, etc etc...we used to use the scrabbling method to join old and new concrete surfaces..we would use a hard broom on the drying concrete to leave a rough surface, then when we came to pour over it we would wet the old surface first to help in the bonding....

I have used drums and drums of the bonding agent ( forget the name, but a creamy thick sludge ) to add in the old concrete mixer, but that was more for mixing up mortar for brick and block work..I have even used ordinary white PVC glue to add to mortar mix, but once again when I was using bricks...

me I would use both methods, scrabble, ( use a kango to rough up if have too ) and use a bonding agent..

[fatbob]

Photo's should show what scabbling is about, the only way to bond to masonry surfaces, a proven technique and the only way reputable construction company's bond the two surfaces, project management company's will insist on this technique.

[fdimike]

Baht

Why not just do a little independant research via the net and satisy yourself and then go with your decision. It's not difficult research and I'm sure you'll come up with the latest technology to solve the problem.

[fatbob]

Yes find the latest technology that hasn't stood the test of time or use a proven method that professionals apply world wide in construction that is fail safe for bonding two masonry surfaces, I wouldn't know, only been doing it for thirty eight years. Its a no brainer, go and ask a structural engineer.
We used a product that claimed to bond and waterproof, it failed and totally delaminated from the slab, cost a lot of money, we are now suing the company, that same company will probably come up as the greatest on the internet.

[Baht Man]

Baht

It's normally a liquid which is mixed with the new mortar or painted on to the old concrete (depending on the brand and instructions). TOA has a product called "Super Bond" and it's normally in the paint section. There are a numnber of other brands as well but the names are normally in English and have something to do with BONDING. The instructions are written in Thai and English on several brands. The stuff looks a lot like "white glue". This stuff is available in every home center here in town to include I believe the newest ones. Another good company is Lanko.

When in Global House and facing the paint aisles from the center aisle this stuff should be to your right. You'll also see concrete waterproofing addidtive and the like in this same aisle.

Thanks again for the info.

[fdimike]

You're welcome. Good luck with your project.

[Baht Man]

Movin' on. =D>