PDA

View Full Version : Tamp sand after screeding??


Redbear
10-13-2005, 10:31 PM
I'm new to the driveway game and am working on just our second one. Done many patios and walks and never tamped concrete sand after screeding. With a driveway does anyone tamp after screeding sand and then top up with a second layer after. I'm guessing it can help to reduce the amount of settling the driveway may do under vehicle pressure but I'm not sure I understand the procedure that is taken to do this. Can anyone elaborate??

cgland
10-13-2005, 10:47 PM
The ONLY difference between driveways and patios is the base thickness. You should never tamp sand under any conditions.

Chris

Rex Mann
10-13-2005, 11:17 PM
We tamp our sand after the pavers are installed.
Most guys that pre-tamp the sand, are using it to
makeup variances in the aggregate. And, the variances are
usually way more the the allowable + or - 3/8-inch over 10-feet.

Peace,

Rex

http://PaversInstalled.Com

Squizzy246B
10-14-2005, 07:14 AM
The ONLY difference between driveways and patios is the base thickness. You should never tamp sand under any conditions.

Chris


Chris, Why Not??

neversatisfiedj
10-14-2005, 07:32 AM
Never tamp sand , look at ICPI standards.

jd boy
10-14-2005, 07:37 AM
if you tamp the sand it will not be drawn up between the joints when you compact the pavers

Squizzy246B
10-14-2005, 07:49 AM
OK, for pavers, got it, right, sorry:blush:

DVS Hardscaper
10-14-2005, 11:15 AM
Ok.

Lets go a little further.

Lets talk about the purpose of the bedding sand, and then we can talk about why you never compact the sand.

The bedding sand is NOT the foundation of the interlocking pavement. Regardless if it is a walk, patio, pool deck, driveway, loading dock, staging area at an airport, etc.

The bedding sand is just that! It is sand that *beds* the pavers!

Ok, now the proper name of pavers is: 'Interlocking Concrete Pavers'

People think the word 'interlocking' derives from the various shapes and sizes that the pavers are offered in.

Nope.

That is not the case!

The term 'interlocking' derives from the construction *system* of the pavement.

The sand is used ONLY to LOCK the pavers into place. Nothing more. The aggregate base is your foundation, your backbone to the pavement.

if you compact the bedding sand prior to laying pavers...you will NOT obtain a satisfactory 'interlock'. The pavers will be suspictable to movement, looseness, and so on.

And, technically you can not use just any 'ol sand as the bedding sand. it must be a washed concrete sand. The sand granuales (sp) are angled, thus they lock together.

Many folks think the joint sand is used primarily for asthetic purposes. They think the joint sand should look like mortar joints on a brick wall. Joint sand is used only to aid in firming up the pavers to prevent movement. its important to fill the joints completely, as it looks better. But we have many clients say "is there enough sand brushed in?", when there is.

So I have learned to explain to the client in my initial consultation of why the sands are used. What they do. And I show them pictures of screeded bedding sand. I explain why too little sand can make a poorly built patio. And I explain why too much sand can ruin a patio. I also show pics of paver joints with the proper backfill of sand, so at the end they are not demanding we make the paver joints look like brick wall joints.

cgland
10-14-2005, 04:48 PM
DVS - Well said!

Chris

Redbear
10-14-2005, 10:34 PM
Thanks for the responses, very thorough. I am wondering about the washed concrete sand however, my main landscape depot does not term it concrete sand but #2 sand and I'm not sure that it is exactly the same thing. Does concrete sand go by any other name or what should I be looking for in the sand. It does appear to be similar.

DVS Hardscaper
10-14-2005, 10:53 PM
Red Bear,

I do not know the answer to that. Maybe someone else here does?

I do know washed concrete sand can be bought from a building supply yd.

I see you mentioned "landscape supply depot".

See, hardscapes is PART of a landscape, but really the materials are available from building suppliers. Not sure about your area, but around here a landscape supply yard does not come close to providing the correct materials for a hardscape project.

Rex Mann
10-14-2005, 11:37 PM
redbear,

You are looking for a coarse grade of sand that has 0% to 1% fines.
Fines are defined as: any material passing the #200 sieve.
Material passing the #200 sieve are defined as clay or silt.
Clay and silt hold moisture, which is not good for an interlocking
pavement system. We want the sand bed to be "free draining".
Do not let someone tell you mason or mortar sand is okay! It has
to many fines and you may end up with the washboard effect on
your pavers.

You can ask your supplier to see a sieve analysis from the quarry.
Look for the % PASSING THE # 200, and keep it between 0 and 1%

Most places do not carry concrete sand. It is not widely used. Try
one of your paver vendors, who sells bulk materials. It is likely they will have the proper bedding material.

Peace,

Rex

http://PaversInstalled.Com