DenpasarHouse

Active Member
Aug 13, 2013
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I'm hoping to put a plastic barrier between the ground floor cement slab and the earth below so as to stop rising damp but my builders don't know where to get any.

I've read on the Internet that this isn't available in Bali, but I thought I try for myself as you never know your luck. I've tried the local Toko Bangunan (small local building supplies shop), Depo Bangungan and Mitra 10 (Gatot Subroto), but I'm pretty sure they don't know what I'm talking about.

Here's what I'd be buying if I was in Australia:

Builders Film Grunt 2m x 20m x 100um Black

Grunt Builder's Multi-Purpose Film is a high quality, black polythene film that can be used in a variety of ways.

Available in a conveniently sized rolls, Grunt Builder's Multi-Purpose Film is ideal for use as a plastic tarpaulin, temporary weather protection during building, moisture barrier under concrete slabs or as a drop sheet.
Temporary weather protection during building
Moisture barrier under concrete slabs
Plastic tarpaulin
Plant protection from birds or frost​

An alternative product, which is probably just the same thing, would be fish pond plastic. Are there any Garden Supplies stores in Bali?

Terimah kasih sebelumnya.
 

DenpasarHouse

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Aug 13, 2013
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Thanks matsaleh, there's some good information there about damp proof course in walls, that's the next thing I'll need to search for.

Thinking laterally, maybe I could just get some cheap vinyl floor covering and use that under the slab instead. Surely any sort of barrier is better than nothing.
 

Populaire

Member
Jun 22, 2011
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Hi DenpasarHouse,

Yes - this is a product range sorely needed in this country. That said, basic best practices should safeguard against the risk of rising damp.

Sloof should be found in every property with a reinforced concrete structure. They are the key component of a building's foundations. But sloof are generally or at least very often below grade - so the sloof itself is not all that often intended as the damp course. The sloof, when below grade - is risen to pad level, generally with a masonry wall. It's at the pad level that the most important factors come into play for damp proofing.

First, pad level should be kept at least 30cm above gardens. The pad itself should also have a "reng" around it's entire perimeter, this reng is a reinforced rib component of the slab - it's basically a perimeter floor beam poured into the slab that sits atop the riser walls from the sloof (note that the sloof however are not only around the perimeter of your slab, rather they cross the grid, correlating with your buildings axis) - the slab rebar ties into this reng. It is probably this reng that Mr. Fixit was referring to as sloof, as this should always be above grade.

But beyond the reng as damp roof barrier - you need to be careful of the typical way of most buildets pour most slabs in Indonesia. In Indonesia, on grade slabs are rarely double rebar reinforced concrete - they're usually a single layer of non-structural rebar (i.e. chicken wire - or it might as well be) with a low grade mix of aggregate and sparse amounts cement - they call this concoction "rabatan" - stay well away from it.

We do our slabs on a well compacted base, on that base we then put down a "lantai kerja" - or working surface. That working surface we then seal with a double coat of Aquaproof - a relatively elastic sealer, which serves two purposes. It aids as a moisture barrier throughout the life of the structure - but it also betters the curing process of the concrete by not allowing the water from the freshly poured concrete to rapidly bleed out into the porous surface of the lantai kerja and beyond.

A good pour on double meshed rebar will then go a very long way in ensuring you won't have moisture rising through the floor or base of the walls. Finally, and this is overkill, but we do it because we like overkill - we seal the top side of the slab with a cement based sealer that doesn't hinder the installation of floor finishings - it's not elastic, but with a proper slab structure it won't need to be.

So even in the absence of some common sense products, it's still possible to find ways to ensure a quality outcome. Hope this helps..


All the best,


Populaire..
 

hinakos

Member
Sep 3, 2008
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Bali + Vietnam
You can always do what most others do here - build your land level up 20cm higher than all your neighbours.

Ensure adequate slope towards neighbours to avoid excess rain soakage during wet season.
 

Markit

Well-Known Member
Sep 3, 2007
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Karangasem, Bali
Our footings go down 2M and the foundations are 30cm above ground level. As we border a rice field in front with coconut forests around and to the back drainage is not a problem even in heavy rains.

So far (3 years) no problem with rising water in any walls - more of a problem with falling water seeping through stairs and other flat areas then getting into walls. Used Sika the best waterproofing available but building abilities were not up to the application requirements (keep off the fecking floor until it's dried!!!).
 

DenpasarHouse

Active Member
Aug 13, 2013
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Thanks davita and Markit, I'll pass this info on to my builders.

What a strange country we live in. I can get sophisticated, chemical additives to waterproof cement but I can't get a simple piece of plastic.
 

DenpasarHouse

Active Member
Aug 13, 2013
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Thanks Populaire, that's a whole lot of great information. I pretty sure I understand all of it except when you say "we then put down a 'lantai kerja'", what exactly is this made of?

Thanks Hinakos, I'm already 40cm above ground height so I hope that'll be enough.
 

Populaire

Member
Jun 22, 2011
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Hi DenpasarHouse,

You're very welcome.

"Lantai kerja" is just a working surface - usually just a mortar mix 1-2" thick, plastered over an already compacted and level backfill.

Never pour concrete straight over backfill - that's the other negative of "rabatan" - its always directly on top of the backfill. The lantai kerja gives you a nice flat solid surface to Aquaproof before you pour.


All the best,


Populaire..
 

hermit

Member
Aug 19, 2010
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Bona gianyar
What about the plastic that is used in growing melons and things like that?Maybe only 1 meter wide,but might be suitable for the walls?
 

DenpasarHouse

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Aug 13, 2013
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That sounds pretty promising and as luck would have it, I'm visiting my brother-in-law's farm tomorrow. Thanks Hermit!
 

no.idea

Member
Feb 22, 2011
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Sanur
We found decent width rolls when building some houses recently. The workers had no idea what it was for. They poked holes in the plastic so the water would drain away and the cement would dry quicker.
 

alex margou

Member
Jul 20, 2013
229
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Heavy duty rubber sheeting is also available at hardware stores. It's used for under-tile flashing and to direct water run-off from roofing, but I don't know if this is close to what you're looking for.

Something like this: Karet hijau / Rubber Green - BAKTI JAYA MANDIRI - Indonesia

Something similar to this can be found in almost all small builders' merchants all over the place. It's called TALANG KARET and comes in long rolls of various widths - 30cm, 60 cm etc. It's a grey rubber sheet about 1cm thick or less, but bonded to one side is a tough plastic coating coloured red to match the colour of roofing tiles. It's very cheap.
 

davita

Well-Known Member
Mar 13, 2012
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Today I thought I saw huge rolls of clear plastic just for that purpose. I say I thought coz it was while in my car and I just got a fleeting glimpse.
It was in a hardware store about 2-300 meters south of Tiara Gatsu supermarket, on the left just past the big Pura, travelling on Raya Kerobokan...if others are in the area maybe can take a better look.
 

DenpasarHouse

Active Member
Aug 13, 2013
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Wow! Thanks for all the help everyone. Can't believe how many people have taken up the challenge.

I can confirm that although promising, the plastic used on farms for watermelons, chillies etc is too thin and wouldn't really withstand coming into contact with steel rebar or probably even the workers boots (Boots! Ha! As if!).

I went to Mitra 10 in west Gatot Subroto yesterday and confirm they've got the Karpet Talang in various widths. The largest being around 90cm...I think. Sorry they didn't have measurements marked. I bought a 1m sample of the 425mm width for Rp.6.900.

According to this site the maximum width available is 110cm. http://www.jayaabadi.org/material/133-karpet-talang.html

Karpet Talang
PROS:
Cheap!
Very strong and is actually meant to be used to waterproof rooves and gutters.
Doesn't attract termites (I stored in our infested guest room last night), so there's no rubber content, it's all plastic.

CONS:
Max width only 110cm, I may have to glue a couple of widths together.
A little too thick to be folded / handled easily.

Thanks Davita, I'll go past and have a look see today sometime.
 
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DenpasarHouse

Active Member
Aug 13, 2013
526
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Thanks for keeping a lookout Davita, but those rolls were foil insulation.

Another idea I had was that thick clear plastic the use for the walls and rooves of green houses. I don't know where I'd get it from but even if I could it's probably not as good as using the Karpet Talang.

So in conclusion, I'm going to with the Karpet Talang. In a few weeks, I'll update this thread with how the whole process turned out. Thanks again everyone.