Concrete hollow block mold

There are plenty of hollow block molds for sale on Lazada and Shopee for about P1.000 each but finding a mold for an 8" block may be a problem. The exterior walls of my house are made of 6", 750 psi blocks and the interior walls are 4", 450 psi blocks. After the cement plaster is applied to both sides the exterior walls are 20 cm (7.75") which is thick enough to hide the columns. My interior walls measure a full 6" after plaster and skim coat.

The strength of a well designed hollow block house is in the columns and tie beams but the hollow block walls are strengthened by filling the cavities with cement or mortar, a vertical rebar every 5th hole and a horizontal rebar every 3rd course of block. The vertical rebar should extend from the bottom tie beam to the roof trusses with a 30x diameter overlap where joined. Here is a photo of the lower tie beams in my 2 story house. You can see the dowels sticking out of the columns for the horizontal rebar and sticking out of the tie beams for the vertical rebar.

@Moon Dog nice reply, I saw the pictures of your house completed and it was very nice. Our place is finally done and the landscaping is filling in faster than I imagined.

I was thinking of making my own blocks when we built our house, but as already mentioned, the strength of the house is mainly from the support beams and columns. At P15 per block, and the time to make all of my own, I just bought the blocks needed. I went to several different suppliers around and had a look at their blocks. Some you could grab the end with your thumb and forefinger and break off a chunk. Some you could not. Obviously you buy from the guy with the blocks you could not. I ended up making a good friend with the owner of a hardware store around me. A very likeable person, good quality and he gives me a discount. Bought most of my supplies there, he didnt have everything we needed.

@Michaelm54 Thanks and congratulations on finishing your house. Our land scaping went quickly also thanks to the cow pasture behind the property. The caretaker let us get all the sod and rich top soil we needed.

@Moon Dog nice.  Do you have a place i can see progress pictures?

Additional question: My friend wants to mix coconut fibre into making of hollow block. Is that doable? What are the pros and cons here?

Additional question: My friend wants to mix coconut fibre into making of hollow block. Is that doable? What are the pros and cons here?
-@mikaelarhelger

CHB are for walls. The compressive strength of CHB is the property that's realized. Fibers are used for its tensile strength. There is no benefit adding coconut fiber in your CHB other than supporting livelihood of the CHB maker. If you're concerned about the CHB being brittle, make sure the maker uses the correct cement/sand ratio that goes in the CHB. Also check they are curing the CHB properly. If you are building a house with mud bricks, fiber in the mud bricks will help.

@erostorch I did assembly a bunch of photos and planned to post them. The work on additional projects ended last week so now I have a lot of free time for the first time in 1 1/2 years so I will make a YouTube slide show.

Here is the lot in June 2020  just before the 24 man crew arrived.

Laid out, holes dug and columns set.

The house today

Bueutiful home.  Goal set

We have been using 6 inch blocks but told the maker I wanted extra cement in the mix to make decent blocks, around 4,000 at an extra 3 pesos per block now, and only one cr@ppy batch of 350, slapped and never happened again. The 10mm horizontal rebar goes in every 2nd course instead of the standard 3 courses. Fence posts on the front boundary 350 x 250 as it's 2.7 to 3M high, the extensions are all 300 x 250 and 16mm vertical rebar with 10 mm rings, all the posts and beams are vibrated while pouring. Some longer tie beams are 16 mm and shorter are 12mm, when mixing concrete in the one bagger they throw an extra square mouth shovel full of cement in. Even the render has extra cement and is 25 to 30mm thick.

The boys think I'm going overboard and wasting money but for another 150 to 200K I know I have a solid building given the last earthquake we had here.

Regarding tie beams, posts and my two bobs worth Steel sizes and placement make a strong skeleton so 4,5 or 6 inch blocks are just an infill that is rendered and again my opinion the render is much stronger than the hollow blocks and ties it altogether.

Cheers, Steve.

An add on, concrete blocks here and most countries are 390 in length, 190 in height and then the width.

Cheers, Steve.

@Moon Dog Lovely home. From start (including planning permission) to finish how long did it take you? Did you use an architect?

@Gezzar It was planned for 8 months but it was closer to a year due to covid and then we added a couple months work with changes and additions. We used a builder from Cebu and it was designed by an architect and executed by an engineer so we have a full set of blueprints for every aspect of the construction and a set of simplified plans for the home owner to go by. The engineer was in the same class as my wife's sister in high school. He is from this barangay in Biliran province but his office is in Cebu. The foreman on the job was very good.

I think our house is one of the smaller jobs. The attached picture is another house the guy built on this island and he built the Harley Davidson dealership in Cebu. I was very close to giving the job to a company called Leyte Builders out of Baybay, Leyte but the wife liked the design of the local guy so he got the job .

If it is a single story bungalow you don't need engineers and architects. My wife and I designed the in law's bungalow and the foreman who was in charge of building our house built the bungalow. A multi level house is a different story. I want to be safe under the suspended slab that is the second floor.

@Gezzar I reread you post and did not reply accurately. We got the notion that it was time to build on the property in January and construction began in June so it was 5 or 6 months planning before construction began. 

Moon Dog - both houses are beautiful.

@Jackson4

Thanks,

I can say a few words that may help others. My house is a bit plain on the inside. It doesn't have the fancy ceilings that are common in the Philippines. It is more like a US house so if you like the fancy ceilings you will have to work that out with the builder.

I wasn't here when the house was under construction. My wife's father, nephews and brothers gave us daily updates and sent photos. We had a chat with the foreman a couple times a week. It would have been better if I were here, especially with the wiring and countertops. On the wiring I would have wanted a panel box with a ground bar that was grounded to a proper ground rod and all outlets to be the 3 hole grounded outlets. The countertop guy did a great job with the granite but he cut out around the entire perimeter of the sink and recessed it and that didn't make sense to me since the sink was designed to set on top of the countertop.

I'm a pretty good HVAC guy and I've installed a few split units in the US. I marked on the drawings where I wanted the 4 aircons and I told the foreman there was no need for the AC outlets he was installing inside the house since the power was outside at the disconnect. Lido put a box outside for power but he also installed outlets inside. Little did I know the the power for Philippine split units connect inside. Two of the outside outlets came in handy for other purposes but the inside outlets made installation simpler and I was the one to install all 4 split units. Kudos to a good foreman.

My main complaint with the house is the exterior paint. I could see large blisters in the paint in the photos sent to me. I had that corrected but when I arrived I saw more bubbles and blisters. I don't know what caused the paint not to adhere properly and the workers that were here when the house was originally painted all had their own opinion. The work was completed last week and the workers were released from the job but their last act was to scrape off the bad paint and repaint the entire house. It costs me the price for 8 gallons of paint and a weeks salary for 5 workers.

@Dave & Ruby Did you get a reply from anybody mate ?

What locality are you ?

AAC are coming now to the Philippines…. Faster to build your house indeed.

check blocktec website indeed