Concrete base question for garage

[shd1970]

So my builder has let me down and can no longer put a concrete base down for me now so i'm going it alone
Measurements are 5m x 2.4m
Its more of a workshop than a garage and i want to get as nice a finish as possible
Also, as we are link detached, there will only be the front edge that needs shuttering

So :

1. Is 100mm hardcore + 100mm of concrete correct / sufficient (its not used for cars, its too narrow)
   
2. Is there a particular mix that i need to ask the concrete company for as i plan to get a delivery rather than mix myself for consistency and to save time and effort
   
3. Are the 5m trowels readily available at tool hire shops
   
4. With the front edge only needing shuttering, what tricks are there to get a nice smooth front edge, rather than when the shutting is removed, it rips away loads of the mix

Thanks in advance all

 

[John D v2.0]

not sure why noone has replied so I'll give it a go
1. see paving expert as they have a lot of information on their website about buildups. We used 100+mm hardcore under out block paving drive and it hasn't moved at all even with cars parked. Just make sure you remove all loose material and whacker the hardcore down well.
2. not sure but good plan on getting it delivered, try to get them to place it for you as well and then you just have to flatten it out. I would imagine you don't have special mix requirements, but ask them what they recommend, they might be helpful. Also NHBC information can be useful as that's all online.
3. don't know what it is but just call them or go in and you might get someone helpful who can give you a few tips too
4. I think you can get shuttering ply and paint on some kind of release paint to prevent sticking. Just make sure what you use is as smooth as possible. Even the DPM would help if you're using one.
On the topic of DPM make sure you consider the levels to avoid wicking damp up into any of the surrounding walls.
And good luck! Maybe someone more knowledgable will comment on your or my posts.

 

[23vc]

3. Bull floats, yeah. But unless you’re well practiced using one, I wouldn’t bother. Tamp it level and get on it with a plastering/flooring trowel later in the day
4. DPM

 

[shd1970]

Thanks for the replies guys

So, a couple more questions please :

1. Is a level of sand absolutely necessary with plastic sheets, or will just hardcore and concrete suffice
2. To save on the labour of having to level the concrete myself as I will be working alone, is there a self leveling concrete mix that can be delivered which needs minimal handling.... basically, it's just shot straight in up to the "fill to line" and is then left

Thanks again

 

[John D v2.0]

Sand is essential to avoid the hardcore damaging the dpm. Most people say an inch but some say 2 inches!
You can get self levelling concrete but I'm sure it's very expensive. I think Hanson/tarmac do one of you check their web site.

 

[DIYhard]

I made enquiries about self-compacting concrete (SCC) quite recently. Company websites make it sound ideal for anybody who has difficulty finding a squad to spread, tamp and float ordinary concrete, and YouTube videos seem to suggest that all you need is one person to wade through the mix with a dabbling board for just a few minutes. Several sources mentioned the need for extra-strong shuttering.

Two local readymix depots knew nothing about SCC, but gave me contact details for their company reps. One rep said his company didn’t have anybody likely to supply it to my area. The other rep said delivery could be arranged, and quoted ex-VAT price £121/m3 (ordinary concrete is about £100/m3 in this area). That price seemed very reasonable … BUT … the rep went on to ask:

1. Have you have experience of using this material?
   
   
2. Do you have the equipment required for handling it?

Another very well respected local company said they would be able to produce SCC, but would not be willing to supply anybody who could not show previous experience of using it.

I chickened out at that stage (discretion or cowardice?) and plan to use normal concrete.

 

[^woody^]

Normal concrete and hire a power float

 

[shd1970]

thanks for all the replies
i'll give it some thought over the weekend

One further piece of advice please
i'm also bringing my garage roof forward a couple of metres
Plan is to install some C16 (47x125mm) vertical bars and joists at 400mm centres between myself and my neighbour (the green lines) which from what i have read, meet the strength criteria allowing access for periodic maintenance
The roof will be boarded with OSB too

But....there will be 1 corner of the roof which is forward of my neighbours that will need some vertical strength (the red line)

I was considering installing something like a 150mm x 150mm wooden post onto a small brick pillar

1. Would 150mm x 150mm suffice ?
2. Is there a particular type of wood that i should/should not use ?
3. Is there some kind of strength rating that i should be looking for ?

thanks in advance as always

 

[^woody^]

Why can't you cantelever it?

 

[rssteve]

Are you planning to cut a chase for lead into the neighbours house? How's that work I'm looking at something similar.

 

[shd1970]

Why can't you cantelever it?

thanks for the reply Woody

My assumption was that the overhang towards my neighbours side would not be strong enough to take the weight of anyone needing to go up and perform maintenance having no vertical support, hence my thought to put a post in place

 

[^woody^]

thanks for the reply Woody

My assumption was that the overhang towards my neighbours side would not be strong enough to take the weight of anyone needing to go up and perform maintenance having no vertical support, hence my thought to put a post in place

I'd be inclined to cantilever it rather than have that awkward post.

If it can't be done with just timber, add an angle or channel section.

Or if you are worried about maintenance you can design it to take a temporary prop just for those rare occasions.

 

[23vc]

Agree with woody, looks miles better without post, and worst case, acro prop. Don’t reckon that’d even be needed tho.

 

[shd1970]

thanks again guys

so can i just check, when you say cantilever, you mean basically, nothing else is required other than the horizontal beams/joists bolted to each house, where the one extends approx 1.5 mtrs on the right hand side, and no vertical support would be required in your opinion on that corner ?

would there be a limit on the length the joist that extends forward of the house, before horizontal support is required ?

as mentioned, i plan to use C16 (47x125mm) vertical joists bolted to both walls and cross joists at 400mm centres

thanks again for the valuable input guys...appreciated

 

[shd1970]

Sorry for the *bump*...can anyone confirm on the following please ?

thanks again guys

so can i just check, when you say cantilever, you mean basically, nothing else is required other than the horizontal beams/joists bolted to each house, where the one extends approx 1.5 mtrs on the right hand side, and no vertical support would be required in your opinion on that corner ?

would there be a limit on the length the joist that extends forward of the house, before horizontal support is required ?

as mentioned, i plan to use C16 (47x125mm) vertical joists bolted to both walls and cross joists at 400mm centres

thanks again for the valuable input guys...appreciated


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