Building a Garage from concrete hollow blocks

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Hi,

I am looking for advice on building a garage.

It will be 5 metre x 6 metre as thats the largest I can go without building and planning permision(floor area max 30 mtr), it will be 2 metre high walls. The base wil be higher than the ground and the land slopes slightly.once the base is done I will put a concrete slope into the garage door (maybe 2 single doors)
There is currently a shed in the space which has power so that will be the power for the garage.
Unfortunatly getting a builder to do this is not an option due to cost so I have to do it myself.

The garage is over 30 metres from the house(or any house)

1/ I need to do the base so need to know what depth and kind I should do. Will a few inches of concrete be enough or do I need it deep under the walls ?

2/ I intend to build with the wide 200mm hollow concrete blocks so that I only have to build the one skin which should save on time and make a sturdy construction. (and render the outside when done)
Will I need to put strengthening bars in of any kind ? and how many rows can be layed in a day ?

3/ The roof I would like to put a tiled roof on but that could change if finances wont stretch to it. Will this make any difference in the building of the walls ?


Thanks for any advise.
 
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Hi

Im intending to do the same sorta thing in the easter break, but will be using solid concrete blocks.

Your foundations depending on ground soil should be at least 400mm if your ground is like mine which is clay and soil and you can drive a peg easily up untill about 250mm in the ground then would recomend 400mm deep and about 600mm wide. Dont take my word for it you have to determine it for your self.

This link should be a good indication for you.
http://www.diydoctor.org.uk/projects/foundation project.htm

Bare in mind the foundations should be lets say 400mm thick but you need two course of block below ground so if the blocks r 215mm high ull need 400mm plus 215 plus 215 which is 830mm dug out to accomdate the 400mm thick foundation and the two courses of block.


Not to sure on your blocks or bars, but I would use bars but will wait for someone else on here who knows more about this to comment, I.e shytalks FNT as they gave me the best advice for my project.
 
Two words "Future Proof". Consider when designing this thing:

1) What is the heaviest, biggest thing you'll ever want to put in there. Make sure the doors are big enough and the floor strong enough (i.e a bridgport mill vs. a car)

2) What is the most power hungry thing you will have in there? and make sure your main incommer can handle it (i.e a fridge vs. an industrial welding kit)

3) Will you need natural light/extractors... etc, plan these things into the design to allow you to add them in the future.

[gah, I'm such an engineer]

Sam.
 
Whatever you do, I'll give you one piece of advice, fit bigger doors! The standard UK single door width is 7', but as cars are now wider its a tight squeeze, so I always recommend that an 8' wide x 7' high door (or doors) is fitted.
 
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Hi

Im intending to do the same sorta thing in the easter break, but will be using solid concrete blocks.

Your foundations depending on ground soil should be at least 400mm if your ground is like mine which is clay and soil
If you are talking about the depth below ground level, in a clay soil you won't have a garage for very long! Clays at that shallow depth are susceptible to seasonal fluctuations in moisture content as well as the effects of vegetation. You need to be 1m deep minimum.

If you are talking about the depth of the foundation itself, I'm not sure where you got that from: if it's table 12 in that link, they are widths for various loads. I would suggest 450 wide Gen1 trenchfill, which will more than adequately cater for the loading from a garage, bearing level dependent on site conditions, stop it off 150 to 225 below ground level, saves laying blocks in the trench.

Please don't place me in the same league as FeyNattyTraveller, I can only aspire to such dizzy heights of wisdom and knowledge ;)
 
hollow blocks are a pain to lay compared to solid blocks.
in simple terms. you have to weigh up how many trowel 'actions' it takes to lay wide hollow blocks.
i reckon its about 9/10 trowel wipes as opposed to 3, and a little fuss, to lay a solid block.
if you need to ask these questions then its likely you will make a mess. (render will sort that i suppose)
you will also be knackered when you have to lift those blocks high.
it will take you longer and hurt your back using concrete. use lightweight blocks and you will get it done quicker. it will cost a bit more but it all evens out. (some poor bugger has to move the blocks to site as well :cry: )

i cant see the need for fancy walls when it is simply a garage.
i think we feel it will be a better job if its built more massive, but is that really needed!... i dont think so.

better to work/play inside a finished garage than hurt your back building a bomb shelter in your garden.

good luck with it. :)
 
If you do opt for 4" blocks, dont forget to add the odd buttress if you are only planning a single skin.
 
Loool shy I can push a peg about250mm deep till it gets hard so I thought if I dig out about 800mm fill it about400mm deep with concrete wudnt that be ok?
 
The reason for 1m depth is to avoid climatic influence on the clay moisture content. But it will probably be ok at that depth; your choice :).
 
I spoke to a building supplies company and they advised to do a concrete slab at 6" min. and that would be ok for a garage.

Is this right or should I go with something else ????

The ground is normal soil, Not clay and not realy sandy.

I also read somewhere that I could do a trench around the edge about a foot deep and fill with concrete and the slab on top of that.

Which would be best ?

I dont want to get the base wrond :eek: :confused:
 
I dont want to get the base wrond :eek: :confused:

Ops look as if you got it wrong already :D


Soil Heave can be caused by the following reasons:

1. "Stress relief" due to the removal of soil from an excavation.

2. An upward seepage of water resulting from a change in the water table.

3. Swelling of the subsoils due to increases of water into the ground resulting from
seasonal changes or from felling or dying trees.

4. Frost action.

There are many plastic clays that swell considerably when water is added to them and then shrink with the loss of water. Foundations constructed on these clays are subjected to large uplifting forces caused by the swelling. These forces will induce heaving, cracking, and break-up both of building foundations and slab-on-grade members.

An increase in moisture content causes clay to swell. The depth in a soil profile up to which periodic changes of moisture occur is usually referred to as the active zone. The depth of the active zone will vary depending on the location of the soil profile and can vary from 1.0m to 5.0m in Southeast England. The active-zone depth can be determined by plotting the liquidity index vs. the depth of the soil profile over several seasons.

MC - PL
Liquidity Index LI = ------------------
LL - PL

Where MC is the Natural Moisture Content, PL is the Plastic Limit and LL is the Liquid Limit of the soil at a particular depth.

A relationship between the moisture content and the liquid limit for swelling clays is given on Figure No. 1. The moisture content of the soil at its Liquid Limit is plotted against the Swell Index, Is, which is the Natural Moisture Content divided by LL moisture content.

The resulting point is plotted on the figure and should fall into one of the four swell bands where swell is <1%, 1 to 4%, 4 to 10%, and >10%.

There are also potentially damaging effects associated with frost action in soils; the expansion and lifting of the ground in winter (frost heaving and frost boiling), and the loss of bearing capacity during the spring thaw. Soils that display one or both of these manifestations are referred to as "frost susceptible". The problem of frost damage is widespread and occurs in temperate regions where there is seasonal soil freezing. The depth of frost is usually about 450 mm in Southeast England. So only digging your footing to 400mm will cause problems in very cold winters.

Frost susceptibility tends to be a feature of silty and sandy clays; that is, soils of low to medium plasticity. The table (below) from the Transport and Road Research Laboratory gives an indication of frost susceptibility and permeability with grading and plasticity index for preliminary identification.

High Permeability Granular < 10% finer than 75 microns. Not susceptible

Intermediate Granular > 10% finer than 75 microns. Susceptible
Permeability Cohesive PI < 20%.

Low Permeability Cohesive PI >20%. Not susceptible

Migration of water and frost heaving are also influenced by the mineralogy of the clay fraction. Clay minerals with expandable structures are able to hold more water, but the water is relatively immobile compared with non-expandable clay minerals. Consequently, strong frost heaving is more likely to be associated with soils where the fines are devoid of montmorillonite and related minerals.

Hope that help you all decide how deep to dig.
 
If it's just sandy stuff then 450mm to bottom of excavation is absolute minimum; and that's usually the toe on a raft foundation (don't just use a slab as suggested, it needs to be a properly designed raft, with rebar: it's cheaper to do simple founds and an oversite slab). I would stick general foundations in at a min depth of 600mm, subject to being in good stuff, not fill or topsoil; 450mm wide will be adequate.
 

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