I have recently watched a few videos of extensions being built and noticed
that in common with new builds ground floors are now solid concrete.
However on one such build block and beam was used with no explanation why?

What would be the reason to favour block and beam over solid concrete, or
is that too going the way of suspended wooden floors? In all cases
extensive insulation was used either under the concrete or on top of the
block & beam and UFH used.

Tricky Dicky wrote:

> What would be the reason to favour block and beam over solid concrete

Speed ... the beams can be hoisted into place and blocks dropped in
between, they can immediately be walked on, have piles of brick/block
stored on top to continue building the walls ... a fairly sloppy
slurry/grout needs to be brushed into the joints at some stage.

On 14/02/2024 16:58, Tricky Dicky wrote:
> What would be the reason to favour block and beam over solid
> concrete, or is that too going the way of suspended wooden floors? In
> all cases extensive insulation was used either under the concrete or
> on top of the block & beam and UFH used.

I was recommended to use block and beam because my floors were very big
and the soil was wet clay with tree roots in it.

The explanation given was that the soil would in time dry out and shrink
and crack any concrete floor laid on it: an air gap under the blocks and
beams allowed for this.,

So I had various internal foundations put in going down quite far to
rest the beams on.

It worked out well.

--
In todays liberal progressive conflict-free education system, everyone
gets full Marx.

On 14/02/2024 17:19, Andy Burns wrote:
> Tricky Dicky wrote:
>
>> What would be the reason to favour block and beam over solid concrete
>
> Speed ... the beams can be hoisted into place and blocks dropped in
> between, they can immediately be walked on, have piles of brick/block
> stored on top to continue building the walls ... a fairly sloppy
> slurry/grout needs to be brushed into the joints at some stage.
>
Whilst that is to an extent true, it's not the general reason. Large
concrete slabs laid on the ground will in time crack and sink due to
soil drying out beneath them and the thickness and amount of rebar
needed to stop this makes the whole thing more expensive than block and
beam, whereas for a small extension, a thinner poured slab is OK.

--
Ideas are more powerful than guns. We would not let our enemies have
guns, why should we let them have ideas?

Josef Stalin

On 14/02/2024 18:53, The Natural Philosopher wrote:
> On 14/02/2024 16:58, Tricky Dicky wrote:
>> What would be the reason to favour block and beam over solid
>> concrete, or is that too going the way of suspended wooden floors? In
>> all cases extensive insulation was used either under the concrete or
>> on top of the block & beam and UFH used.
>
> I was recommended to use block and beam because my floors were very big
> and the soil was wet clay with tree roots in it.
>
> The explanation given was that the soil would in time dry out and shrink
> and crack any concrete floor laid on it: an air gap under the blocks and
> beams allowed for this.,
>
> So I had various internal foundations put in going down quite far to
> rest the beams on.
>
> It worked out well.

+1 for the conservatory we had built. It was also considerably cheaper
to use block and beam than solid concrete.

--

Jeff

On 14/02/2024 20:54, Jeff Layman wrote:
> On 14/02/2024 18:53, The Natural Philosopher wrote:
>> On 14/02/2024 16:58, Tricky Dicky wrote:
>>> What would be the reason to favour block and beam over solid
>>> concrete, or is that too going the way of suspended wooden floors? In
>>> all cases extensive insulation was used either under the concrete or
>>> on top of the block & beam and UFH used.
>>
>> I was recommended to use block and beam because my floors were very big
>> and the soil was wet clay with tree roots in it.
>>
>> The explanation given was that the soil would in time dry out and shrink
>> and crack any concrete floor laid on it: an air gap under the blocks and
>> beams allowed for this.,
>>
>> So I had various internal foundations put in going down quite far to
>> rest the beams on.
>>
>> It worked out well.
>
> +1 for the conservatory we had built. It was also considerably cheaper
> to use block and beam than solid concrete.

I didn't think it was that economical unless you purchase a lot of
beams, as they need to be made to your dimensions.

On 14/02/2024 21:34, Fredxx wrote:
> On 14/02/2024 20:54, Jeff Layman wrote:
>> On 14/02/2024 18:53, The Natural Philosopher wrote:
>>> On 14/02/2024 16:58, Tricky Dicky wrote:
>>>> What would be the reason to favour block and beam over solid
>>>> concrete, or is that too going the way of suspended wooden floors? In
>>>> all cases extensive insulation was used either under the concrete or
>>>> on top of the block & beam and UFH used.
>>>
>>> I was recommended to use block and beam because my floors were very big
>>> and the soil was wet clay with tree roots in it.
>>>
>>> The explanation given was that the soil would in time dry out and shrink
>>> and crack any concrete floor laid on it: an air gap under the blocks and
>>> beams allowed for this.,
>>>
>>> So I had various internal foundations put in going down quite far to
>>> rest the beams on.
>>>
>>> It worked out well.
>>
>> +1 for the conservatory we had built. It was also considerably cheaper
>> to use block and beam than solid concrete.
>
> I didn't think it was that economical unless you purchase a lot of
> beams, as they need to be made to your dimensions.

According to the structural engineer 10 years ago:
"I think the answer to this is 1.5m deep trench fill footing (+
clayboard and beam and block floor) this has to be the cheapest and best
solution. To build a raft you have to dig out to 750mm + an extra 1m to
perimeter of conservatory and backfill with crushed rock (type 1) and
build a 250mm rc raft on top of that."

--

Jeff

Fredxx wrote:

> I didn't think it was that economical unless you purchase a lot of
> beams, as they need to be made to your dimensions.

Some that I have kicking around, have their length scrawled into the wet
concrete on the bottom, but I'd have thought it was equally possible
they make various stock lengths, and just use a sawto chop a few inches
off to make your size?

On 15/02/2024 07:31, Andy Burns wrote:
> Fredxx wrote:
>
>> I didn't think it was that economical unless you purchase a lot of
>> beams, as they need to be made to your dimensions.
>
> Some that I have kicking around, have their length scrawled into the wet
> concrete on the bottom, but I'd have thought it was equally possible
> they make various stock lengths, and just use a sawto  chop a few inches
> off to make your size?
>
From memory all the strength is in the beams - the blocks are pretty
weak and easily cut

--
In a Time of Universal Deceit, Telling the Truth Is a Revolutionary Act.

- George Orwell

On 15/02/2024 07:31, Andy Burns wrote:
> Fredxx wrote:
>
>> I didn't think it was that economical unless you purchase a lot of
>> beams, as they need to be made to your dimensions.
>
> Some that I have kicking around, have their length scrawled into the wet
> concrete on the bottom, but I'd have thought it was equally possible
> they make various stock lengths, and just use a sawto chop a few inches
> off to make your size?

Correct. From memory, around ten 4m beams were required. Most of these
were used full length, but the conservatory had a 2m x 2m bridge from
the patio doors to the main 4m x 4m section (to avoid building over the
sewer access). The beams for the 2m bridge were made from the 4m beams
with a cutting disk.
<https://ibb.co/sw7zvtt>
<https://ibb.co/T4KhC9V>

--

Jeff

The Natural Philosopher wrote:
> Andy Burns wrote:
>
>> Some that I have kicking around, have their length scrawled into the
>> wet concrete on the bottom, but I'd have thought it was equally
>> possible they make various stock lengths, and just use a sawto  chop a
>> few inches off to make your size?
>
> From memory all the strength is in the beams - the blocks are pretty
> weak and easily cut
Yes, I was talking about the beams, you can see where the reinforcing
wire was cut at the ends

On 14/02/2024 18:56, The Natural Philosopher wrote:
> On 14/02/2024 17:19, Andy Burns wrote:
>> Tricky Dicky wrote:
>>
>>> What would be the reason to favour block and beam over solid concrete
>>
>> Speed ... the beams can be hoisted into place and blocks dropped in
>> between, they can immediately be walked on, have piles of brick/block
>> stored on top to continue building the walls ... a fairly sloppy
>> slurry/grout needs to be brushed into the joints at some stage.
>>
> Whilst that is to an extent true, it's not the general reason. Large
> concrete slabs laid on the ground will in time crack and sink due to
> soil drying out beneath them and the thickness and amount of rebar
> needed to stop this makes the whole thing more expensive than block and
> beam, whereas for a small extension, a thinner poured slab is OK.

I much prefer suspended floors - it gives simple routes and access to
add/change plumbing and wiring in the future, without having to get
everything down the walls from the floor above.

On 15/02/2024 13:40, SteveW wrote:
> On 14/02/2024 18:56, The Natural Philosopher wrote:
>> On 14/02/2024 17:19, Andy Burns wrote:
>>> Tricky Dicky wrote:
>>>
>>>> What would be the reason to favour block and beam over solid concrete
>>>
>>> Speed ... the beams can be hoisted into place and blocks dropped in
>>> between, they can immediately be walked on, have piles of brick/block
>>> stored on top to continue building the walls ... a fairly sloppy
>>> slurry/grout needs to be brushed into the joints at some stage.
>>>
>> Whilst that is to an extent true, it's not the general reason. Large
>> concrete slabs laid on the ground will in time crack and sink due to
>> soil drying out beneath them and the thickness and amount of rebar
>> needed to stop this makes the whole thing more expensive than block
>> and beam, whereas for a small extension, a thinner poured slab is OK.
>
> I much prefer suspended floors - it gives simple routes and access to
> add/change plumbing and wiring in the future, without having to get
> everything down the walls from the floor above.
>
That may be true of wood, but it aint true of block and beam

No way you can punch through that to add pipes. or wires

ALL my services come down from above: Nothing is routed underfloor
except vents for combustion devices.

--
"The most difficult subjects can be explained to the most slow witted
man if he has not formed any idea of them already; but the simplest
thing cannot be made clear to the most intelligent man if he is firmly
persuaded that he knows already, without a shadow of doubt, what is laid
before him."

- Leo Tolstoy

On Wed, 14 Feb 2024 16:58:42 -0000 (UTC), Tricky Dicky
<tricky.dicky@sky.com> wrote:

>I have recently watched a few videos of extensions being built and noticed
>that in common with new builds ground floors are now solid concrete.
>However on one such build block and beam was used with no explanation why?
>
>What would be the reason to favour block and beam over solid concrete, or
>is that too going the way of suspended wooden floors? In all cases
>extensive insulation was used either under the concrete or on top of the
>block & beam and UFH used.

I walked past a new build development in Coalville (Leics) in January
that was just out of the ground and the block and beam floors had just
been installed. Coal mining country but the street is otherwise full
of 100+ year-old terraced houses.
https://www.google.co.uk/maps/@52.7175935,-1.3764528,3a,75y,141.87h,84.33t/data=!3m6!1e1!3m4!1skCYlirr1p97mZQm2d5oR4g!2e0!7i16384!8i8192?hl=en&entry=ttu

Tricky Dicky <tricky.dicky@sky.com> wrote:
> I have recently watched a few videos of extensions being built and noticed
> that in common with new builds ground floors are now solid concrete.
> However on one such build block and beam was used with no explanation why?
>
> What would be the reason to favour block and beam over solid concrete, or
> is that too going the way of suspended wooden floors? In all cases
> extensive insulation was used either under the concrete or on top of the
> block & beam and UFH used.
>

Our house is block and beam on two of three floors (it is split level). On
those floors, there are significant gaps to ground level.

When a new house was built next door, the ground floor was also made of
block and beam. At the rear, due to the slope of the land, there is
probably room for a basement to be added.

On 14/02/2024 16:58, Tricky Dicky wrote:
> I have recently watched a few videos of extensions being built and noticed
> that in common with new builds ground floors are now solid concrete.
> However on one such build block and beam was used with no explanation why?
>
> What would be the reason to favour block and beam over solid concrete, or
> is that too going the way of suspended wooden floors? In all cases
> extensive insulation was used either under the concrete or on top of the
> block & beam and UFH used.

Beware the camber!
Our 4.5m x 8.5m balcony was done in block and beams.

There is a very significant camber can't remember exactly but it's in
excess of 10mm fall awy from centre to end of beams.
This also has the problem of adding a bit of deflection to the surface
if you step quite heavilly in the centre so if insulating on top of the
block @ beam you'd still need to screed over the top before laying the
insulation.

On Wed, 14 Feb 2024 16:58:42 -0000 (UTC)
Tricky Dicky <tricky.dicky@sky.com> wrote:

> I have recently watched a few videos of extensions being built and noticed
> that in common with new builds ground floors are now solid concrete.
> However on one such build block and beam was used with no explanation why?
>
> What would be the reason to favour block and beam over solid concrete, or
> is that too going the way of suspended wooden floors? In all cases
> extensive insulation was used either under the concrete or on top of the
> block & beam and UFH used.

In 2021 my wife and I purchased a 50 year old bungalow in poor
condition. It was built on a slope.The front has timber floors, the
rear half, all concrete. A garage at the side was too dilapidated to
be used for anything.

We had it razed and an extension built in its place.
The builder asked me do you want a timber or concrete floor?

The timber floors contribute to draughts so I chose concrete.

When construction got to the point of starting the floor I was amazed
that they were using block and beam. I didn't ask any questions. After
laying a liner they laid 100mm of Celotex both on the floor and in the
ceiling and something similar in the cavities of the three outside walls.
They added another liner followed by a cement screed.

Now that I am using it, the heat loss is palpably minimal.

Good luck with your choice.

Alan

--
Linux Mint 21.1 kernel version 5.15.0-94-generic Cinnamon 5.6.8
AMD Phenom II x4 955 CPU 16Gb Dram 2TB Barracuda