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Hi all,

Can we use solid block for internal walls and bricks for external walls? What would be the disadvantage of this kind of construction? I feel this could cut some cost. On reading various texts, I have come to a conclusion that bricks have better thermal properties and sound proofing on comparison with solid concrete blocks. The drawback of brick seems to be cost and little extra space it occupies. On the other hand solid concrete blocks reduces cost and space but lack thermal properties. So using it for partition walls could free up a little space. If we use solid concrete block for pillars and internal walls, and use bricks for external walls, will there be any problem related to structure?

Thanks in advance,
K Shriram

The cost difference is not really a lot if you go with such a setup. Better to stick either with complete Brick construction or complete block construction. To be honest, bricks from Malur work out to almost the same price as using solid concrete blocks.

Thank you sir. What would be the rough minimum cost of a decent quality brick?

Per my engineer, there're no str problems. As per quote given to me last month, good quality brick (non wirecut) vs cement block (non apco) extra cost was 32 Rs per sft for exterior walls.
Inner walls cost diff wasn't much and he was ready to absorb. I went ahead with cement blocks for all.

Thanks for your input sir. I am in process of deciding whether to go for brick or cement block for my walls. I am planning for a 2100 sqft duplex house on a 1500 sqft plot. My contractor has quoted 10% extra for brick construction, thereby taking the cost to ~Rs.4200000. With solid block, I would be saving around Rs. 400000 which the contractor will pass on to me. Following are my understanding about the advantages and disadvantages of brick and solid block:

Pros of solid block:
1. Stronger than brick wall
2. Saving of approximately half an inch of thickness thereby increasing the carpet area a tad bit.
3. Initial cost savings (In my case it is around Rs.400000 or ~10%)
4. Termite resistance
5. Better finish
6. Less prone to cracks?? (not sure on this ==> I presently live in a KHB apartment constructed with solid block and I see no cracks in walls inside the house and very minor cracks externally, given that this was constructed by government and is more than 15 years old)

cons of solid block:
1. Thermal properties (but I am not sure how this will apply to Bangalore which has only around 3 months summer but with comparatively cooler nights)
2. Sound insulation

Pros of bricks:
1. Good thermal properties
2. Better sound insulator
3. Time tested in India

Cons of bricks:
1. Cost
2. Availability of good bricks.
3. Prone to more cracks compared to concrete block?? (Not sure on this)

Another thing that I want to understand is regarding the heat absorbing and heat releasing properties of clay brick vs concrete block. My understanding is that during summers during the day time, the brick wall absorbs the heat from outside and retains the heat and when night sets in, slowly the absorbed heat is let inside the room, thereby keeping a "cooler" day temperature and a "warmer" night temperature. Whereas the concrete block transfers the external temperature fluctuations quicker inside the room. Is my understanding correct? If this is the case, on a hot summer day, at around 10 PM in the night which room will be cooler? Is it the brick wall room or concrete block room? I would like to have a pleasant/cool temperature at night rather than day. Cooler winters are okay with me.

I am very much concerned about the temperature within the house because I want to go with natural ventilation as much as possible rather than relying on AC. Though I will have an AC, I want to minimize the use of AC and rely on natural ventilation and use AC to the bare minimum during peak summers. I am of the opinion that it is possible to achieve this given the Bangalore's pleasant climate.

Experts please provide your valuable opinion on this subject and also correct me if my understanding about brick and blocks is wrong.
Please provide your valuable inputs on my doubts.

Hi,

I am not an expert, but we recently built our house. We too were confused about bricks vs solid blocks, we finally decided on bricks for the thermal properties.

My understanding is that this decision has a bearing on the column and beam design. If bricks are used, then 9" wide columns are cast. On the the other hand 8" wide columns are used with solid block construction.

Please check with your structural engineer, if this decision has a bearing on the structure.

Hi ddn and others,

I have decided not to mix concrete blocks and brick for the construction. Let us keep this thread for discussing the thermal properties of brick vs block and which material is most suited thermally for Bangalore climate. We have to continue this thread because in this forum or over the web we do not have a concrete understanding of how the temperature fluctuates inside the rooms given Bangalore's temperature. This would help us in making an informed decision. To start with, there is an article on thermal mass. Please have a look on this article:

http://www.yourhome.gov.au/passive-design/thermal-mass

In the above article, the thermal lag (The rate at which heat is absorbed and re-released by uninsulated material is referred to as thermal lag) is almost same for concrete and brick at 6.9 hours and 6.2 hours respectively. This means for a west facing wall, considering that the wall would heat up till around 4.30PM, 6.5 hour lag would be approximately be 11 o clock (+ or - 30 minutes) for brick and concrete block. This could mean that 11 o clock, the time when we go for sleep would be uncomfortable since the heat is released at this time into the room. This also shows that thermal lag is almost same for both brick and concrete. What do you think guys?

The volumetric heat capacity is 2060KJ/m^3K and 1360KJ/m^3K for concrete and brick respectively. So this means with less energy the brick heats up? Does this mean that brick heats up quick and cools down quick? whereas the concrete heats up slow and cools down slow? Does this mean nights will be warmer in concrete walled houses than brick walled and days will be cooler in concrete walled house than the brick walled?