a bit of advice on screeding please???

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a bit of advice on screeding please???

  • grano sand and cement

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  • spotmix

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liverpool_plasterer

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im about to screed a decent sized floor in a new build extension. "spotmix" have previously been in and put a "too shallow" uneven base in. i would appreciate some advise on my next steps.. whether to run level batons 1st, whether to run batons around the perimeter of the room and work to that level??... .does previous floor has to be bonded?? also advice on mixes or to get another load dropped by spotmix... any advise would be much appreciated!!
 
Normally you are governed by a door openings or you are given a datum to work to , i screed freehand don't use battons , floor screed is normally a 4-1 mix, im not sure what you mean by previously put a uneven base in ??? but welcome to the forum , Have you ever seen a screed being layed ?
 
when you say a too shallow uneven base, do you mean its been concreted and kept low so the screed will be thick? ??? i only do small rooms free hand, prefer to use rules/batons as you are quaranteed to get it bang on. the bloke i work with does it free hand and its never spot on so i think thats what steers me away from it.
 
yes i have a door to work from. the concrete base that has been put in it lower than this so needs a screed bringing it up to level but its a deven area so was thinking to use battons. yes i done a term screeding in collage a few years back but havent done much since without supervision. thanks for your advice :)
 
Is There any regs for the job ? Normally there should be a dpc membrane put in and insulation (cellotex or similar ) to bring the sub base up to around 65mm for a screed .
 
church said:
Is There any regs for the job ? Normally there should be a dpc membrane put in and insulation (cellotex or similar ) to bring the sub base up to around 65mm for a screed .
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Church is spot on in all he has said (as usual), by the time you've put your battens around Church or me would have the screed almost done. If you keep using battens you'll never move on and learn the correct method.
 
thanks church you have alot of knowledge looking back through the forums!!....

well...the base and insulation has already been put in by the builders put its too low to the entrance of the room (the datum line) and patheticly uneven, ive already ran 3 level bands the full length of the room with sand and cement to work from and in some places it needs 50mm other places it doesn't even need 10mm

any do's or don'ts before i start tomorrow. im planning a 3to 1 mix semi dry.??? any advice would be highly appreciated!
 
I've had the same before and what I did was this, tell the builder that they can either have a step up into the room (not likely), gun up the oversite to allow the correct depth of screed (again not likely) or take up the insulation just before you screed and either replace with some that's thinner or use none at all, but make it clear that as they are doing all the prep work any come backs are down to them. And guess what, the last option is always the one they go for.
 
flat boy skim said:
who puts an expansion joint around when screeding
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Now days the insulation should come up the walls to the depth of the screed which would act as an expansion joint not that it's needed in normal houseing.
 
essexandy said:
I've had the same before and what I did was this, tell the builder that they can either have a step up into the room (not likely), gun up the oversite to allow the correct depth of screed (again not likely) or take up the insulation just before you screed and either replace with some that's thinner or use none at all, but make it clear that as they are doing all the prep work any come backs are down to them. And guess what, the last option is always the one they go for.
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it already has no insulation! i was suprised at this but the bulider said the regs didnt ask for any. its just a concrete base so no way i could take out the high points its soild. ive already suggested a step..theres no way!! i did tell him its likely to crack he said thats down to him! :-\ so any suggestions on mixes?? grano or just sand cement 3/1 so its stronger???
 
Stronger mixes are not all ways better ,im sure kirk johnson has done a post on screeding some where ?
 
Screed the floor twenty mm below the door opening level, just leaving the concrete bare where it needs to be left and then when fully dry they or you can latex the whole floor over the screed and concrete to the correct level.
 
essexandy said:
flat boy skim said:
who puts an expansion joint around when screeding
Click to expand...

Now days the insulation should come up the walls to the depth of the screed which would act as an expansion joint not that it's needed in normal houseing.
Click to expand...
I thought that was for a thermal break...
 
essexandy said:
Screed the floor twenty mm below the door opening level, just leaving the concrete bare where it needs to be left and then when fully dry they or you can latex the whole floor over the screed and concrete to the correct level.
Click to expand...

yeh sounds a good idea, by latex do you mean self level? is this ok to go down straight over the concrete?
 
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