Concrete roofs

[HeijoshinCool]

I'm in LOS but returning to build in the states next month.

 

In BKK now but when I lived down south I noticed a lot of new construction with concrete roofs. Either flat or lightly slanted. From the inside, some were obviously separate slabs (probably lifted into place), some were poured.

 

Anyone that has any details on the methods used I'd love to hear back.

 

Building 20 minutes in from Gulf of Mexico and the house will have monolithic slab floor, 8x8x16 inch block with rebar and hollows filled with concrete. Wanted to tie it all into the roof with welded rebar. Area, as you might know, is hurricane/tornado prone. 

 

I'd be happy to travel to see one getting built, if you have knowledge of such. 

 

Thanks.

[Excel]

Wait to hear back from anyone too but just wondering will you be using TIC ( Thermal Insulating Concrete ) ?. Becoming quite common in UK/Europe , don't know about the US but never seen it here or know of its use here .  Considering it for my next build if experienced contractors are available but as I said not found any yet experienced in that method. 

[HeijoshinCool]

23 minutes ago, Excel said:

Wait to hear back from anyone too but just wondering will you be using TIC ( Thermal Insulating Concrete ) ?. Becoming quite common in UK/Europe , don't know about the US but never seen it here or know of its use here .  Considering it for my next build if experienced contractors are available but as I said not found any yet experienced in that method. 

.

 

Good question.

 

I Don't know.

 

I've got enough concrete experience to plan and work with it but don't know 1) the price difference, and 2) the work methods.

 

This will be a 450 sf house. I can do most of the work myself with the occasional extra pair of hands. If the TIC requires more labor/experience/cost, I doubt I'd use it.

 

Besides, I've always done well with, If it ain't broke, don't fix it. I don't like trying new things at my age:) 

 

So, Since block is cool, and there are large trees overhead, I'm not too worried about lots of insulation. If code demands it, I'll just fur out the interior walls.

[canopy]

If you were smart you would use ICF for everything--the floor, the walls, and roof. ICF can take big hurricanes, tornadoes, earthquakes, fires, just everything. Longevity, Insulation and sound proofing second to none. Cost is very cheap to build and will actually save money over time because of reduced maintenance costs, lower home insurance premiums, lower utility bills, and means you can install smaller, cheaper hvac systems due to the excellent thermal properties. People in ICF homes when hurricanes roll in don't even know it unless they look outside. I can't understand why someone would choose to build with anything else. ICF would be the most excellent type of house build for Thailand if you could get it or anywhere else.

[canopy]

dup

[HeijoshinCool]

1 hour ago, canopy said:

If you were smart you would use ICF for everything--the floor, the walls, and roof. ICF can take big hurricanes, tornadoes, earthquakes, fires, just everything. Longevity, Insulation and sound proofing second to none. Cost is very cheap to build and will actually save money over time because of reduced maintenance costs, lower home insurance premiums, lower utility bills, and means you can install smaller, cheaper hvac systems due to the excellent thermal properties. People in ICF homes when hurricanes roll in don't even know it unless they look outside. I can't understand why someone would choose to build with anything else. ICF would be the most excellent type of house build for Thailand if you could get it or anywhere else.

.

 

Okay, I'll check into it. I have no familiarity with it (as I admitted above), but I'll start some investigating. 

 

Does it "work" any different than 4000psi? Take more manpower? 

 

At 450sf, with minimal roof eaves, and steel shutters and doors, even regular concrete will stand up to a hurricane/tornado/fire.

 

The insulation is of great interest, however.

 

Sound, not so much...I'm on acreage with ag neighbors and a pond full of frogs and trees full of crickets. Sleep like a baby.

 

Is ICF more fireproof? 

[canopy]

10 hours ago, HeijoshinCool said:

I have no familiarity with it

It's usage is growing every year for good reason, but yet ICF was invented 50 years ago and yet most people still have never heard of it despite it being so cheap and good.

  

10 hours ago, HeijoshinCool said:

Take more manpower? 

 

ICF takes very little manpower and the build takes very little time. The process is stacking foam blocks like lego's, dropping in rebar along the way, then pouring it full with concrete mixers. In fact some homeowners even stack the ICF blocks themselves to save even more money on labor. Typically ICF costs 5% more than an American (stick frame) home. It's a no brainer.

 

10 hours ago, HeijoshinCool said:

Is ICF more fireproof? 

 

Absolutely yes.

 

 

 

[HeijoshinCool]

Thanks for the post.

 

Now I know what you guys ae talking about. I saw a house put up a few years back with these.

 

All good, except i"m more interested in a concrete roof and how they are doing it here in LOS.

[BritManToo]

On 4/22/2021 at 4:32 PM, HeijoshinCool said:

In BKK now but when I lived down south I noticed a lot of new construction with concrete roofs. Either flat or lightly slanted. From the inside, some were obviously separate slabs (probably lifted into place), some were poured.

My concrete roof arrived this morning, around 10 large concrete planks (4m x 0.5m), after the crane lifted them into place they were welded together. I think they will pour another inch of concrete on top. They arrived, unloaded and were gone within an hour.

 

 

[Excel]

On 4/23/2021 at 8:00 AM, canopy said:

If you were smart you would use ICF for everything--the floor, the walls, and roof. ICF can take big hurricanes, tornadoes, earthquakes, fires, just everything. Longevity, Insulation and sound proofing second to none. Cost is very cheap to build and will actually save money over time because of reduced maintenance costs, lower home insurance premiums, lower utility bills, and means you can install smaller, cheaper hvac systems due to the excellent thermal properties. People in ICF homes when hurricanes roll in don't even know it unless they look outside. I can't understand why someone would choose to build with anything else. ICF would be the most excellent type of house build for Thailand if you could get it or anywhere else.

That's the rub, I have researched but can find no instances of it used here in Thailand so hence no experienced contractors. 

[canopy]

42 minutes ago, HeijoshinCool said:

All good, except i"m more interested in a concrete roof and how they are doing it here in LOS.

Use ICF for the roof and the floor too.  Why are you so interested in how it is done in Thailand? I thought you were "Building 20 minutes in from Gulf of Mexico".

 

[canopy]

34 minutes ago, Excel said:

I have researched but can find no instances of it used here in Thailand so hence no experienced contractors. 

Concur. It might be technically possible to order ICF blocks from alibaba or something like that but being able to execute the build with proper bracing , scaffolding, pumping trucks, and never having any experience doing it before ICF is not a suitable option for at least 99.999% of the people in Thailand. Better to settle for q-con.

 

[HeijoshinCool]

8 hours ago, canopy said:

Use ICF for the roof and the floor too.  Why are you so interested in how it is done in Thailand? I thought you were "Building 20 minutes in from Gulf of Mexico".

 

.

 

Well, because you don't see it done in the states, it's all shingles or metal, but I've seen it here and it appears to have been done quite successfully and the climates are almost identical.

 

 

[HeijoshinCool]

9 hours ago, BritManToo said:

My concrete roof arrived this morning, around 10 large concrete planks (4m x 0.5m), after the crane lifted them into place they were welded together. I think they will pour another inch of concrete on top. They arrived, unloaded and were gone within an hour.

 

 

.

 

Now, THAT is what I'm talking about. 

 

I wanted to make my own "tongue & groove"  planks, and crane them in position. 

 

That's the easy part. What I don't know is how it's waterproofed here in LOS.

 

Love more pics if you have them!

 

Thanks!

[BritManToo]

23 minutes ago, HeijoshinCool said:

.Now, THAT is what I'm talking about. 

I wanted to make my own "tongue & groove"  planks, and crane them in position. 

That's the easy part. What I don't know is how it's waterproofed here in LOS.

Love more pics if you have them!

Thanks!

No tongue and groove, these are roughly pushed together then welded by a iron spike in the center each side. The ends have 4 spikes of iron poking out. All a bit wobbly and gappy at the moment. Eventually they'll be tiled on the top, but I have no idea what they'll be doing next, probably tomorrow or on Monday. I'll update as it happens.

[canopy]

  

34 minutes ago, HeijoshinCool said:

Well, because you don't see it done in the states...it appears to have been done quite successfully...and the climates are almost identical.

Thai's rarely build for the climate, instead they build to be as cheap as possible and deal with the heat as an afterthought. I would not use the word successful to describe Thai houses using concrete planks roofs. Builders often don't understand the edge bonding necessary to hold the planks planer. Without this the edges tend to go out of whack over time and cause problems. Waterproofing in Thailand is usually done at the floor level--when the roof leaks they have buckets on the floor to catch the water. This is not a joke. It is extremely common practice and leaks are common. They have absolutely no idea how to do proper flashing work or waterproof membranes. And they don't care. To them a plastic bucket is a cheaper solution.

 

Wouldn't it make more sense to make an ICF roof to get the best of both worlds? Your roof can be beautiful exposed concrete like you want, hurricane proof, cheap, and at the same time very well insulated and comfortable inside.

 

[HeijoshinCool]

12 hours ago, canopy said:

  

Thai's rarely build for the climate, instead they build to be as cheap as possible and deal with the heat as an afterthought. I would not use the word successful to describe Thai houses using concrete planks roofs. Builders often don't understand the edge bonding necessary to hold the planks planer. Without this the edges tend to go out of whack over time and cause problems. Waterproofing in Thailand is usually done at the floor level--when the roof leaks they have buckets on the floor to catch the water. This is not a joke. It is extremely common practice and leaks are common. They have absolutely no idea how to do proper flashing work or waterproof membranes. And they don't care. To them a plastic bucket is a cheaper solution.

 

Wouldn't it make more sense to make an ICF roof to get the best of both worlds? Your roof can be beautiful exposed concrete like you want, hurricane proof, cheap, and at the same time very well insulated and comfortable inside.

 

.

 

I totally agree with your observations about Thai building....in general.

 

However, for 4 years  I frequented two different buildings (businesses) that had the plank roof. One was a coffee shop, another a shipping company. Neither ever had a single leak, not even during the rainy season in Nakhon Si Thammarat.

 

So there must be a right way and a wrong way.

 

I have emailed the local cement factory near my construction site, asking if they offer ICF. If they do, I'll pursue info; if not, it's so rural it would be a moot point. The next nearest cement supplier is 90 minutes away....

 

Thanks for the continued input.

[HeijoshinCool]

13 hours ago, BritManToo said:

No tongue and groove, these are roughly pushed together then welded by a iron spike in the center each side. The ends have 4 spikes of iron poking out. All a bit wobbly and gappy at the moment. Eventually they'll be tiled on the top, but I have no idea what they'll be doing next, probably tomorrow or on Monday. I'll update as it happens.

.

 

Thanks.

 

Well, making the forms T&G would not be difficult. Yes, I'm interested in updates. Rainy season is coming, and I won't start building my place for another three to four months, so you might have more feedback by then.

 

What is the use of your building?

[BritManToo]

Builders just arrived with a lorry load of sand, chips and cement along with steel mesh.

Looks like they're going to pour an inch of reinforced concrete on top of the roof slabs.

 

Downstairs is a garden room, no walls or windows but I might put them in later.

Upstairs is a large patio outside our bedroom, the misses is already planning to drag a mattress outside to sleep on when the weather is hot and dry. I'm imagining sitting out with Gin and Tonics with a nice breeze in the evenings.

[BritManToo]

This will be finished by lunch-time.

 

[canopy]

3 minutes ago, HeijoshinCool said:

So there must be a right way and a wrong way.

Don't be fooled: just because something works right now is no guarantee it was done correctly or that you would get good results by repeating a bad design. The kind of problems of doing it wrong won't necessarily show up right away and can appear in time after seasonal movement, settling, wear, and other factors. The good thing about building in the US is there are building codes and inspections to make sure the right way is performed and the result is guaranteed.

 

Now if you are making a flat roof in Thailand, wouldn't it make a lot more sense to use q-con ceiling planks instead of legacy concrete planks? q-con's are a perfectly engineered design, load bearing, tongue and groove, light, cheap, and provide excellent heat insulation all in one.

 

 

[HeijoshinCool]

2 hours ago, canopy said:

Don't be fooled: just because something works right now is no guarantee it was done correctly or that you would get good results by repeating a bad design. The kind of problems of doing it wrong won't necessarily show up right away and can appear in time after seasonal movement, settling, wear, and other factors. The good thing about building in the US is there are building codes and inspections to make sure the right way is performed and the result is guaranteed.

 

Now if you are making a flat roof in Thailand, wouldn't it make a lot more sense to use q-con ceiling planks instead of legacy concrete planks? q-con's are a perfectly engineered design, load bearing, tongue and groove, light, cheap, and provide excellent heat insulation all in one.

 

 

.

 

I'm not easily fooled. Was on my first jobsite for all summer at age of 4.

 

Sure that would make sense, but I can't source them in the States, and like I said, my area is very rural. I could make my own forms and make them; we'll see. 

 

Not a mask in sight, even in the stores, and half the pickups have gun racks....with guns.

 

Not a lot of choice in material sourcing....

[BritManToo]

3 hours ago, canopy said:

Now if you are making a flat roof in Thailand, wouldn't it make a lot more sense to use q-con ceiling planks instead of legacy concrete planks? q-con's are a perfectly engineered design, load bearing, tongue and groove, light, cheap, and provide excellent heat insulation all in one.

The crane that delivered my plain concrete planks, also had a few of those q-cons on it, but they were much bigger than my roof. Roof poured now.

 

[canopy]

  

36 minutes ago, HeijoshinCool said:

I could make my own forms and make them

It seems you are set on these concrete planks because you saw them in Thailand and liked them. But making a structural beam needs to be technically sound.  Who will analyze things like the spans, specify the thickness of the concrete, compressive strength, the rebar schedule, the minimum edge overlap, and so on? The path you are on does not seem like it will pass building codes in the US and thus will not be approved. Besides, you seem to be asking in the wrong forum. Better to ask in your geographic area to get the best answers from experts on how to achieve your goals. ICF is huge in your area because it's so cheap and so good. People say every several years the savings in utility bills more than pays off the little extra they paid. And when the next cat4 storm rolls through you'll be loving your house.

 

[canopy]

3 minutes ago, BritManToo said:

also had a few of those q-cons on it, but they were much bigger than my roof

 

q-cons ceiling panels come in various lengths and thicknesses to suit. The advantage of the q-con's is you don't need to pour a slab over them like that, saving that money and also get a well insulated roof automatically.

 

[BritManToo]

Just now, canopy said:

q-cons ceiling panels come in various lengths and thicknesses to suit. The advantage of the q-con's is you don't need to pour a slab over them like that, saving that money and also get a well insulated roof automatically.

 

I don't know anything about building, I hired a local builder that did an extension down the road I liked the look of. He charged the policeman 260,000bht inc walls, windows and electrics, I was charged 150,000 without (he asked for 180k).

 

So I haven't saved any money.

[stubuzz]

5 hours ago, BritManToo said:

This will be finished by lunch-time.

 

 

Was a waterproofing add mix used in the concrete?

[BritManToo]

Just now, stubuzz said:

Was a waterproofing add mix used in the concrete?

Nope, but they'll be tiling over the concrete.

I'm not sure how much water can get through concrete planks + an inch of reinforced concrete + tiling cement and tiles.

[canopy]

13 hours ago, BritManToo said:

I'm not sure how much water can get through concrete planks + an inch of reinforced concrete + tiling cement and tiles.

People who build showers for a living understand that water goes right under the tile floor so they install drains that catch water below the tile level. In Thailand people don't understand this and 2nd floor showers often leak down to the first floor. So if a hairline crack forms in the roof slab it's probably going to be all over and such a crack will likely form directly over one of the plank joints due to the stresses which is precisely where you wouldn't want it and drip down the seams. A waterproofing agent in the mix will not stop this. In Thailand building is in the stone age with nothing but guesswork and associated problems. Developed countries and smart thai builders know how to make flat roofs 100% waterproof. A membrane with flashing to the house wall is excellent for this.

 

 

 

 

[sometimewoodworker]

On 4/24/2021 at 7:22 PM, HeijoshinCool said:

.

 

Now, THAT is what I'm talking about. 

 

I wanted to make my own "tongue & groove"  planks, and crane them in position. 

 

That's the easy part. What I don't know is how it's waterproofed here in LOS.

 

Love more pics if you have them!

 

Thanks!

It’s the normal way to make floors and flat roofs in Thailand you will find many building threads showing that being done. Mine is on CoolThaiHouse .