building sand - is this correct?

[markyyyyyy]

Went to builders merchants to get my sharp sand and cement to mix for a mortar bed, and they reccommended building sand instead of sharp sand, so i went with their suggestion - will building sand be suitable for my project as below?

i'm resting my timber frame for log cabin on top of concrete blocks as follows, working from underground upwards:

1. 100mm hardcore
2. 4:1 ratio of building sand : cement
3. concrete block
4. Damp proof membrane. Damp proof membrane
5. timber frame
6. log cabin

TIA

 

[tony1851]

Building sand is the usual type for mortar - you would find sharp sand very difficult to work with.

 

[markyyyyyy]

Building sand is the usual type for mortar - you would find sharp sand very difficult to work with.

great thanks! so their advice is correct!

 

[markyyyyyy]

On another note - do you think i need to rest the concrete block on a mortar bed or can i just lay it on a 100mm compacted layer of hardcore? There will be 10 blocks around the perimeter of the log cabin, and the total weight of cabin is approx 800kg

 

[noseall]

Building sand is the usual type for mortar - you would find sharp sand very difficult to work with.

If you think of ratios and logic apply them to both types of sand, it all becomes easier. Screed sand particles are say 5 times bigger than soft building sand. If you use a big shovel instead of a trowel and lay huge beds and lay huge blocks then it all makes sense.

 

[scbk]

On another note - do you think i need to rest the concrete block on a mortar bed or can i just lay it on a 100mm compacted layer of hardcore? There will be 10 blocks around the perimeter of the log cabin, and the total weight of cabin is approx 800kg

Too late now as you're bought the materials, but you can put them on a thin layer of sharp sand over the hardcore - the sand is just so you can get them all level