House Construction Questions

[Samoerai]

There are no measurements mentioned in the video, but from the way it is portrayed it does seem somewhat shallow, yes. Besides that, i think it is an interesting video for people who want to acquint themselves with building their own house.
I quite like the design; it's not easy to build something nice of around 6x8m on a rather small plot of land.
High ceilings and a void/2nd floor where the warmer air will flow to with enough angin² (ventilation holes) to ensure good air flow. The higher walls have extra beams imbedded for structural integrity and the footplates in the back of the house allow an extra room on the 2nd floor. No lack of rebars in the concrete cast beams, columns and plates. In my area I doubt many developers will meet these standards.
The talang dalam (gutter) is bound to give one a headache, probably sooner than later. But that's the trade off you have to make in designs like these.

shallow foundation and footing

It's technical terminology used by soil engineers.

 

[jstar]

Do you mean plastic gutters integrated in the walls start leaking after awhile? Or the the gutters directly made in the mortar/cement? In The Nerherland nowadays they build / intergrate the gutter pipes also in the walls. Drama.

The ones made from the cement. Those always have their vertical exhaust pipes integrated in the walls. Obviously looks better from the street. I’ve seen quite many issues with those as well.

Here for small houses they practically don’t use the PE with the rubber fittings or the black PP (Geberit) with ‘welding’ system. They are rather rare since it’s obviously more expensive and workers don’t know how to apply those. So in most residential dwellings* the grey/white PVC exhaust pipes are used and they’re always glued. The disadvantages are that it can not withstand extremely high temperatures, make more sound and give more resistance on the inside of the pipe which can obstruct. (And of course the ‘C’ in its name is not very environmental friendly.)

* In high rise buildings you see the PE/PP much more

 

[Samoerai]

The disadvantages are that it can not withstand extremely high temperatures

I saw the workers glue those pipes together, yes. Also the sewer pipes they glue together. Did not know .. the glue cannot withstand high temperatures. Hmm ... I am used to throw hot water in the drains. Just to kill germs and the eggs of those sewer flies. ... better not do that again, right?

 

[jstar]

The hot water once in a while will be fine. But try it with baking soda to remove the grease etc.

The problem is that the pvc glue becomes hard as plastic or glass and that breaks when there‘s movement. So it’s safer when in concrete. And esp. on a roof (if you have a solar system or water tank) it can be risky, with the extreme temperatures and the sun.

Can take years though.

 

[jstar]

the pvc glue becomes hard as plastic or glass and that breaks when there‘s movement

I saw a worker recycling some pvc parts by heating up the connectors with a torch. The glue became liquid again and he could pull the pipe out of the connector. And then he used it again. Smart but without considering if the shape or the consistency of the pvc could have altered of course.

 

[centurion]

I am renovating an old building now and putting new vertical gutter pipes out of the building (plastic). Previously they were inside, leaking and making the plaster inside and outside crack.

The building is from the 1970s and the concrete and rebar are pretty solid (steel in the foundation is 16, others are 12). At that time in Jakarta, the sand was from the Kali river, making good concrete. Now the sand is mostly from the sea.

 

[jstar]

Previously they were inside, leaking and making the plaster inside and outside crack.

Yeah, even without leaking it will create problems. They don’t seem to understand that different materials don’t go very well together. If you put a pipe in a thin wall, you need to be prepared for condensation. Not only that, because of movements, expansion, shrinkage, etc. it is wise to apply a net* on the areas that can crack. They think I’m crazy when I talk about that.

*This is a fiberglass net that reduces the risk of cracks in the plaster. Otherwise every repair is practically useless and issues will return.

 

[Samoerai]

Yeah, even without leaking it will create problems. They don’t seem to understand that different materials don’t go very well together. If you put a pipe in a thin wall, you need to be prepared for condensation. Not only that, because of movements, expansion, shrinkage, etc. it is wise to apply a net* on the areas that can crack. They think I’m crazy when I talk about that.

*This is a fiberglass net that reduces the risk of cracks in the plaster. Otherwise every repair is practically useless and issues will return.

View attachment 2897

How to Use Fiberglass Mesh to Repair Plaster Walls

Plaster walls are quite easy to repair when cracks appear. All you need is a fiberglass mesh tape and drywall joint compound and your wall will look good as new.

homeguides.sfgate.com

 

[jstar]

Something else that you might have encountered here, are the ‘exploding’ floors. Then the tiles are pushed up volcano effect. And it can be with a big scary bang.

Couple of reasons; over here the main issue is temperature deviation. The beton or semen underneath moves, expands and shrinks. Tiles are being pushed sideways but can’t move.

Obviously installing the tiles too close to each other (the trend is to practically have no grout) doesn’t help.

Now another important reason is that they put the tiles in the wet cement. There‘s nothing really wrong with that -somewhat antiquated- method.

But it’s better to have them finish the subfloor first and let it completely dry. Then use the special glue cement that is flexible. They do sell that over here. It allows for a certain movement. Also great for areas prone to earthquake.

But as so often, many workers have no experience with that method and are reluctant to use it.

Also, always demand they ‘comb’ the cement glue and don’t take shortcuts by applying 4 or 5 dots on the tile. For adhesion but also, very important, against noise (you don’t want empty space under the tiles).

.

 

[centurion]

M

Yeah, even without leaking it will create problems. They don’t seem to understand that different materials don’t go very well together. If you put a pipe in a thin wall, you need to be prepared for condensation. Not only that, because of movements, expansion, shrinkage, etc. it is wise to apply a net* on the areas that can crack. They think I’m crazy when I talk about that.

*This is a fiberglass net that reduces the risk of cracks in the plaster. Otherwise every repair is practically useless and issues will return.

View attachment 2897

metal "chicken mesh" is also doing the job.

 

[Samoerai]

Something else that you might have encountered here, are the ‘exploding’ floors. Then the tiles are pushed up volcano effect. And it can be with a big scary bang.

Wow, not yet seen this effect of exploding floor.

they put the tiles in the wet cement. There‘s nothing really wrong with that -somewhat antiquated- method.

Yes, I have seen the workers do this. After a while, I checked the floor by tapping on the tiles and when the floor on that spot sounds 'kosong', I asked the workers to 'pasang' the tile again. I was surprised to see how much 'semen' or better said 'sand' the workers removed.

 

[jstar]

metal "chicken mesh" is also doing the job.

Nope, that’s quick and dirty DIY. Most importantly, even if galvanized, over time it will rust. Which comes through the paint and nothing can stop that.

 

[jstar]

Wow, not yet seen this effect of exploding floor.

Many times. And very annoying since after years there is not way to get those original tiles anymore. You don’t know where they come from or they are not produced anymore. So then you‘re almost forced to replace the whole floor or make some kind of ‘fancy‘ pattern. Frustrating.

 

[centurion]

Nope, that’s quick and dirty DIY. Most importantly, even if galvanized, over time it will rust. Which comes through the paint and nothing can stop that.

Good plasters and/or additives that go in plasters have anti-humidity and anticorrosive effects. If your plaster/ mortar is done properly, no worries.

 

[Ruserious]

Some great tips here. Any suggestion on what to watch for when they replaster a wall to stop it cracking later?

 

[centurion]

Some great tips here. Any suggestion on what to watch for when they replaster a wall to stop it cracking later?

Are they stripping the wall to the brick before the new plastering?

 

[Samoerai]

Some great tips here. Any suggestion on what to watch for when they replaster a wall to stop it cracking later?

One needs an experienced worker to plastering a whole wall and before replastering make sure to cover the whole place with plastic sheets. It will be messy.
If you only want to repair the cracks, make sure the worker slightly enlarge the crack in the wall with a chisel. Only then can you close the crack with plaster.

 

[jstar]

I would want to know first what the situation with the existing wall is. Why are there cracks? Is it an outside wall with exposure to sun, wind and rain? Or just a straight forward internal wall between two rooms? With the former, you need much more treatment, obviously best would be externally but that’s often not possible so then you might consider to ‘sacrifice’ the brick wall. So apply a water resisting layer on the inside. (Which normally should be your last resort.) In one case I had drywall installed, not a big success. In another, a new internal wall was built against the existing one, very good insulating results.

If it’s an internal wall, don’t let the plaster go to the ground but stop a couple of cm higher behind the plint. That avoids rising moisture.

Also, first do a test whether your walls are suitable for directly applying plaster. You can do this by rubbing over the wall with a wet sponge. The wall should dry in about five minutes, then your wall doesn't have to be treated, although it never hurts. If your wall dries much faster, then it is too porous and it is best to treat it with a fixative primer. If it takes longer than 5 minutes you have a surface that is too smooth and you still need to treat it with an adhesive primer.

Over here they quite often use a (rather pure) grey cement mixture instead of white gypsum.

 

[Samoerai]

then it is too porous and it is best to treat it with a fixative primer.

I was looking for a fixative primer at the Depot Bangunan the other day. They have all kinds of primers and brands. Not sure which one I had to buy. Can you recommend one?

 

[jstar]

You know Saint-Gobain from the Gyproc drywall right? Over here they’re also represented but with the so called MU (Mortar Utama) brand. They also have the flexible tile glue I was talking about which is not so easy to find but you probably need their plasterplus. That one dries slow if used as primer. I think the code is 300 something. The advantage is that you can apply a very thin layer of plaster afterwards. Their acrybond product as liquid, is more suitable if you still have old layers of plaster.

Ah, Kaizen also has some rather good primer solutions.