The Concrete Hollow Block House

I am a Newbie here having just joined the site today, I'm from Scotland and just the other day I turned 70yrs, I guess I am now officially a Coffin Dodger?

I first dipped my toe into the water of PH some 12yrs ago, I retired and moved over there to live around 8yrs ago, still retaining my house in Scotland and very thankful that I did this, as at this time I am presently living back here and have been for the last 3 months.

Some 5yrs ago I had the idea to buy Land and build my own house, of course the obvious choice was to use the standard CHB method and for about 5mins I considered to do this, however the main problem with this method as I saw it was; any house built in cementitious materials has a tendency to heat up during the day only to release this stored heat during the night, of course the simple remedy is to have AC and bear the cost of high Electricity usage? But then I thought what if the house was insulated surely there has to be a great deal of merit in this method no matter where in the world you live, but just about everyone else seemed to think this method is applicable only to countries that have severe Winters.
Anyway I got my head down and researched alternatives to CHB, I guess I may have used up hundreds of hours in this research before I had the confidence to go down a different road to most others, also during this time I found many good reasons for not using CHB's perhaps around 10 or even more of them? one very good reason is; they do not fare all that well in Quakes, during such, many that are killed it is often with falling masonry, then there is the modern trend to build such houses with skinny cosmetic pillars and beams, this being another major flaw.

The method I used was; stud walls clad with Hardieflex with the studs being steel C channel, the cavity between the inner and outer cladding was filled with Rice Hulls for Insulation. The roof sheet material is of high grade uPVC and requires no insulation, in its light cream colour there is very little heat transfer through this.

welcome to the site

Welcome and good idea Dave.

I think most people here use CHB because it's the only thing, apart from native, that the local builder know how to use...

There are quite a few alternatives to CHB here but they tend to be used on larger projects - that's to say I was politely ignored when I enquired about 300 blocks for my planned extension

Welcome to the site, Dave. Are you missing Valencia yet? (jimeve)

I'm missing the place more than you can imagine, especially my Family there.

Actually your local builders really don't know what they are doing either in CHB or the Native Bamboo Bahay Kubo, the original Bamboo house had a roof pitch of around 60 degrees, the idea behind this was to quickly shed the water, now they tend to build with a low pitch 30 degree roof and these retain the water after it stops raining and rots the grasses, giving it no more than a 7yr lifespan, where the higher pitched roof would extend the life of it to 25yrs or more, I have seen one very good example of a traditional bamboo house and this was a work of art where the joints are all drilled and splined, to then be roped off, this allows the joint to flex in high winds, now they just bang them together with nails splitting the Bamboo, a huff and a puff will just blow them away.

When it comes to using CHB's very little skill is required all they are doing is stacking Lego blocks in the rough form of a house, this has the resilience of something close to a sponge cake, for it then to be frosted over with the icing, this being the applied mortar render, usually the mix they use for this is too strong something close to 2 or 3 to 1 when it should be closer to 5 of sand to 1 of cement, added to that often they will use the more expensive pure Portland type of cement where the cheaper blended is much more suited for this application, this has a longer pot life ( which is rarely a consideration for the Pinoy construction worker) and less prone to thermal cracking.

I have observed the building of many CHB structures and everyone of them had one Major failing, for example; The Septic Tank, just about all of them are done in CHB, they start off with the concrete slab complete with the added re-enforcing steel, the steel extends upwards to provide strength to the CHB walls, once the walls are done they are then rendered inside with a water proofer added into the mix, when the guy on the mixer remembers to do this? there you have it, a perfectly sealed Tank from which no effluent material can escape apart from the leaching section at the far end, all good you may think the steel has been protected from the non neutral perhaps acid? effluent which is likely to be highly corrosive to the steel, but what about the outside usually the blocks are left bare with no render at all, these soft blocks absorb water much like a sponge leaving the steel unprotected from the outside, a Septic done in this manner will have a lifespan of around 10 to 15yrs, the water pressure from inside bursts them open, Septic's should only be done is concrete or plastic and never in CHB, even if rendered on the outside there is likely to be a void somewhere in the render so this is not worth the consideration.

This problem is not only in the Septic's there, it also applies in the CHB house, mostly they are only rendered from slightly below grade upwards and have no render down to foundation level, so there is nothing protecting the steel from moisture in this area, however the house will last a bit longer than the Tank as there should be no water pressure from inside, so I would Guess this will be good for 25yrs before the cracks appear provided there has been no serious Quake during this time? this problem could easily have have been resolved in the initial stages of the build, if an 8inch thick stem wall (a term used for the wall from foundation to around 8inch above grade) had this been done in concrete with a water proofer added to the mix, in this way the steel would be well protected from ground moisture, even better is to just build the whole house in concrete, in this you will sleep better at night, provided you have large AC units.

Many Foreigners try to over engineer the construction process here in order to show the local builders how it should be done.
This usually results in unessasarily over priced structures that cannot be sold without losing around 50% of their investments if they ever had to sell.
It's true that any block made from cement or clay acts as a heat sink or a potential battery if left in the Sun.
The answer is do not allow the sun or rain any exposure to your walls. This can be accomplished very easily with a smart design that incorporates 100% wall shading.
Also,very simple techniques in roof design that promote high levels of ventilation are imperative when thinking about building a house in the tropics.
CHBs are not really an important element when it comes to structural integrity as long as the engineering plan is followed.
Reinforced Columns and beams represents the strength. The blocks are largely just space fillers that are fixed to Columns and beams with rebar.
Of course,in reality,many local cannot afford to follow the engineers plans and compromises are made.I guess they just do the best they can with what they have.
Also,I am pretty certain that local Architect's get their inspiration from U.S states like New England for their clients.
These types of Doll houses are not very suitable here. If I were to design a solar oven in the Philippines,it would be of a similar design!
With the cost of power rising up to 20 Peso per Kwh,these building planning decisions are becoming quite important now,especially if using ACs to keep a solar oven cool.

My house is large and spacious with double front doors and a back door which are left open, also five large windows downstairs also left open. They have mossie screens and metal bars to keep out thief's.
Upstairs we have a large hallway with double doors with are left open and again bars and mossie screen, so we have a nice breeze coming through the house.
Top floor is all open apart from the fire wall, and a roof over hangs the whole house, that gets really cool.
So we don't need air-con, been in it for 8 years. Our electric bill is 2, 500 pesos a month and that includes outside light that are on all night.
It's how you design the house with good ventilation.
Also Daves House is really good design with the panels and rice hulls for insulation. Seen some photo's that Dave kindly shown.

Building your own house in PH and especially if you are a hands on person like myself, this fast tracks you into understanding just how Fecking useless Pinoy construction workers are, you really have to work with these guys to understand this, all of the ones I worked with suffered from arrested development, they are only good for showing a bad example and the way not to do things, I should add that I liked my workers I only had three all that is required to build as I did, they were good hard working guys, very honest and have become family friends, but they were useless when they first come to me, with some training and advice from me there was a vast improvement to their skillset towards the end of the job, but much time and money was wasted getting there.

A smart designed home for me would never be done in CHB, this is far from being smart and in my brutally honest opinion and I would go as far to say it is just Fecking Dumb, there are just too many variables in this type of build and the potential for so many things to go wrong, added to that the construction workers have no understanding that Cement has a limited Pot Life, or how that extra pail of water added into the mix reduces the strength by around 50%, it is quite rare to find a concrete vibrating tool on a site in PH, construction workers think they are doing a fine job giving the forms an odd knock with their little toffee hammers.

Anyone of our age group should remember back in the 60's in UK was the start of the clean air movement and white meter electric, in these times they were building homes with concrete floors and installing underfloor heating, existing homes were getting their coal fires de-commissioned and having Night storage heaters fitted, the idea behind this was to use the cheaper white meter electric produced during the night when there was little demand for it, the storage heaters had a large concrete block inside them, this was heated during the night and the vents in the cabinets were opened during the day to give off this heat, so there you have it, a CHB house takes on the heat of the sun during the day and is just a Night storage heater in reverse, even with shading (I cannot see how this can easily be done without some compromises to the natural light level inside the house?) this takes on the higher ambient temperature during daytime and keep the house uncomfortably warm during the night. In light of this building an insulated house was a no brainer to me.

I am 100% in agreement that the house design most prominent in PH originates from the US and WTF do they know? I believe it was them that also brought the Dumb CHB method over to PH, I also fail to understand why Foreigners invest so much money in some of the very large houses there and as you say they are unlikely to have an ROI, my small 75M2 house is perfectly adequate for our family of 4 after all we spend most of our time outdoors, another one of my better ideas was to prepare it to accommodate a couple of rooms upstairs in the Attic in the roof space turning it into a Chalet Bungalow, this has not been done other than the stairs are already in place, this being a very cost effective way to increase the living area of a house but never used in PH, using uPVC roof sheeting ( a lot less noisy than a hot tin roof when it rains) and lots of ventilation, my attic is quite cool and very suitable to this idea.

Use the steel stud and hardieflex method for your extension, you will not regret it.

I did build a hardieflex clad workshop here using 4inch steel C roof purlins.
Its OK for what I need but the space had two negative issues. First is exterior noise such as Neighbour's X Mas Karaoke and the morning chorus from Chooks and other noise entering the interior. Only thing to really block heavy acoustics believe it or not is solid mass. Not only is rice hull combustible ,it is also not much good for noise insulation.
The second negative is security. My workshop wall has half inch hardiflex on the out side and one quarter on the inside. If I lost my key and I wanted to get in,all I would need is 30 seconds and a hammer.
We built a small 100 sqr meter apartment here in a similar way but we filled the cavity with a 123 dry concrete mix. If you are interested,I will message you some images of it under construction.
Our biggest lesson was it was a far more expensive method than CHBs. Almost 1/3rd more than our usual build costs here.
To each his own.
If you do not try these things then you will never know I suppose.

I agree that the steel stud and hardieflex method on its not very affective against noise, however once filled with the Rice Hulls I would suggest it to be pretty dam good, but I agree a solid non insulating wall is best for this, rice hulls are self consolidating, try poking your hand into a bag of hulls that has been sitting for a day, you are unlikely to even get the length or your fingers, once the cavity is filled the walls are fairly solid, no Pinoy can kick their way through this wearing Flip Flops even a CHB wall is not all that difficult to break into with an ordinary hammer , once the outer render (The Icing on the Cake) has been burst the rest is fairly easy and comes away like a (sponge) Rice Hulls may be combustible but you almost need a Blowtorch to set them alight, I know this from experience this has been tried and tested by me, from what you say, I can guess you never did fully research the use of the Hulls and much of what you are suggesting appears to me to be guesswork on your part? Here is part of an article I copied and pasted from the Internet; (Rice hulls themselves are a class A thermal insulating material because they are difficult to burn and less likely to allow moisture to propagate mold or fungi. It is also used as roofing after mixing it with mud and water. Particle boards and cardboard Rice hulls are also used to make particle boards and cardboard) In the US it meets the building Code requirement for use as an insulating material.

Unfortunately our house was nowhere near a Rice Mill and we had to pay for delivery of the Hulls this cost us P60 per bag and three bags were needed to each 8'x4' section of wall often Mills give them away free or at most charge p10 per bag.

I never did do any real costing of the material price, what I can say is, the Kitchen was done as an extension to the main build, the material cost for this was P15K for (9mtrs of wall at 2.44mtrs high) the steel stud wall was done in a day this was day 1, day 2 a Sunday and the workers day off, I run the electrics and the waste drain for the Sink, Day 3 the cladding was done using 9mm hardie to both sides, with the fill and fair to the boards on day 4 and all ready for painting, I should say the house was built on top of a Monolithic slab again a far superior method to that of a strip foundation as used with CHB, the final finish to the walls of this is far superior to that of any CHB wall, the work was done by two men under my supervision and some minor assistance from myself, so the final cost was p17,400 when the wages were added to the material cost.

If this wall had to be done in CHB I would have no idea of the material cost? on your suggestion that figure may be around p10 to 11K, I am assuming you can only give a fair estimate to material cost? but what about the manhours no way is it possible to get this done using CHB in 48 manhours.

Building this same wall in CHB this is normally done using 3 men two Masoons as they like to call themselves and a labourer on the mixer, it will take them a minimum of 2 days to build the blocks, more likely to be 3? 2 days to render the outside, a half day to channel the walls (using the tried and tested pipe and nail method) for the electrics, non of the above can be done on consecutive days, time is needed for curing at each stage, then there will be a further 2 days for the render to be done to the inside, so in my wild guestimation I would suggest this would all take a very minimum of 6 days using 3 men, overall I would suggest the CHB method to be quite Sh!te all things considered and it takes 3 times the manhours to build the house walls.

The saving to be made not needing to use AC in an insulated house would more than pay for the extra cost to build the house walls, only this being affected in the stud and hardie method, the floor and roof stays the same (I am not convinced that it is all that more expensive) also it will reduce the time of the overall build, having a big saving in manhours.

The other week I was posting on another Ex-Pat site (Dumaguete Info) and there I suggested that a fire wall between two Semi detached houses could be done using the stud and hardie method filled with a concrete mix with around 50% of rice hulls added to it, I was always meaning to try this method on a smaller panel but never did get around to it?

Thanks for the offer to send me the Pics this may have some interest for me and perhaps many others on the site?

I wonder how electrical installations would cope packed inside smoldering bio char?
Not something I would risk in order to find out.
I have a friend that used palay husk for cavity walls once but he mixed it 5.1 with Pozzolan cement.

Would that prevent it from Charring in a house fire? I doubt it.
Not for me thanks but if if you guys know better,then Crack on!
I wish you luck with your future construction endeavours,
Just not for me thank you. I,ll stick with my CHBs and rebar from now on.
When in Rome..

Building a House with cavity walls to then fill them with Rice Hulls, would present an extremely low fire risk, especially when the hulls are contained between the inner and outer skins of Hardieflex with this having a very good fire rating, in that example of the Video you posted after two hours the complete pile of Hulls had not burnt/smouldered out, I would suggest in this type of build you would have plenty of time to get out of the house in the event of a fire, added to that there is so little chance for it to become a raging inferno, I would go as far as to say there is a much greater risk present in a CHB house, (I would suggest Quakes are much more common than house fires over there) if ever there was to be a serious Quake, these blocks are liable to crumble and fall on your head, is this event your chances to evacuate the house are very slim?

If you or anyone else have even just a passing interest in the properties of Rice Hulls as an insulation material check out this Link; Slide 1 (esrla.com) I would say anyone with a consideration to go ahead and build an insulated house in PH should consider this method above all else, with this being so cost effective but still performing just as well as most other propriety materials made for this application.

After the shell of the house was constructed it was logical for me to consider doing the kitchen units using the same method, this I have done and these cabinets are there to stay with no risk of damage from TERMITES, the doors may be susceptible to this, these I made myself out of MDF however I have reason to believe MDF is not a favourite to them? another problem I found in most of the Kitchens in the various houses I rented there was that musty foul smell was always present in the Kitchen cabinets, I think I may have resolved this problem with mine as every unit has a screened vent to the outside.

The Kitchen cost me P25K and that included the high grade sink. the countertop is tiled that was a big saving. With the house being only 75M2 I needed to build a compact staircase to be able to access the upstairs attic space, I managed this using and alternating stair pattern, sometimes known as Pork Chop stairs, this is all done in Steel C channel and Hardieflex.

Thank you Dave - I take it you know how to weld ?

It's just that we already have a very good steel frame on the roof and the extension was basically going to extend that out on the back and on the side(s)...

The problem I have here is labor, hard to find and if you can they are expensive, not good at the job and always looking to pinch the materials and/or take a time out...

No welding is required in Steel Stud framing and Roof Trusses can be done in the same material, using my method the 1.2mm steel in the wall frames for the walls are only slotted in to each other initially it is only when you attach the hardie sheets they are then fixed together using Hardie Drive screws through the sheet material into the steel, these screws are tipped with a drill bit on the end, they are capable of drilling into steel that is 3.5mm thick, for the Trusses Tek screws with a drill point would be used, perhaps better to up the game a bit and use the 1.5mm steel C channel or even 2mm if the truss had a long span?

Actually I can give good advice on welding in PH, by far the best method for there is to use a Flux Cored Mig welder, I bought the Lotus brand on-line for P5K around 60x1kg spools of wire were used with this and it never failed us and is still going, it only takes 20 to 30mins practise with this to get used to it, then you can produce a strong weld perhaps not so pretty initially but it does not take all that long to get to a point where you can weld like a professional, the beauty of this over a standard stick weld is you do not need to strike and Arc this does it all for you, with this and a self darkening helmet you are good to go, this really is amazingly easy anyone can do this, even a Non Scotsman.

Thanks - like this one ?