Hi, I'm looking for some guidance with a screeding task I have to do in the next couple of days.
I'm self-building a corner extension to the side of my kitchen and rear of my garage and also converting the rear 2m of the garage to a utility room.
The existing kitchen floor level is around 40/50mm higher than my concrete slab in the extension part so I need to make this up with screed. Additionally, the floor in the utility part in the garage needs raising 110 to 130mm and this will be done with 50mm celotex on a dpm then 60 to 80mm screed.
The extension area is approx 2.5m x 3m and the utility is approx 2.5m x 1.8m. I'm mixing the screed with my son and have sand/cement arriving tomorrow. I've also ordered the fibres that you can add to strengthen the mix.
1. The concrete slab is a couple of months old and has a fairly rough texture. It was simply tamped level with a wooden joist and had light rain on it just afterwards. I'm thinking it is rough enough to give the screed a good enough key to bond to. Other than cleaning and vacuuming do you think it will need any more in the way of preparation so the screed gets a good bond?
2. I'm unsure what to do about the strip where the new screed will cover over the old cavity wall which has been removed down to dpc. Clearly the screed is going to go from being bonded to the concrete slab transitioning to a strip approx 300m wide where it will be sitting on the dpm from under the slab + the old dpc from the original wall. I can't imagine it will bond to this. Should this be reinforced with chicken wire or similar? Or will the fibres that I'm adding be sufficient?
3. Similar to above. At the back of the old garage wall, the bonded screed of the extension will transition over the old single skin dpc of the rear garage wall into a floating screed over the celotex. Should this area be reinforced or will the fibres be enough?
4. I'm also a bit green when it comes to mixing the screed. I have the use of an electric mixer which sits on the floor. I'm unsure of the best process for converting the sand/cement which will be at the front of the house, into screed that is needed in the extension. I'm thinking that it will be impossible to get the mixed screed from the mixer into a wheelbarrow as the mixer is too low, therefore it would be best to have the mixer in situ. How long is it recommended to mix the screed for before it is fully mixed? Is it best to add the ingredients in a particular order?
5. I'm thinking of laying the screed in one big strip with a baton on one side for levels and the existing screed on the other. This will be approx 2.5m wide. Is this feasible or will it be much harder? It avoids the need for a central rail and the hassle that entails. It doesn't need to have a perfectly smooth finish as I'll be tiling over it.
Many thanks for any help that is offered.
I'm self-building a corner extension to the side of my kitchen and rear of my garage and also converting the rear 2m of the garage to a utility room.
The existing kitchen floor level is around 40/50mm higher than my concrete slab in the extension part so I need to make this up with screed. Additionally, the floor in the utility part in the garage needs raising 110 to 130mm and this will be done with 50mm celotex on a dpm then 60 to 80mm screed.
The extension area is approx 2.5m x 3m and the utility is approx 2.5m x 1.8m. I'm mixing the screed with my son and have sand/cement arriving tomorrow. I've also ordered the fibres that you can add to strengthen the mix.
1. The concrete slab is a couple of months old and has a fairly rough texture. It was simply tamped level with a wooden joist and had light rain on it just afterwards. I'm thinking it is rough enough to give the screed a good enough key to bond to. Other than cleaning and vacuuming do you think it will need any more in the way of preparation so the screed gets a good bond?
2. I'm unsure what to do about the strip where the new screed will cover over the old cavity wall which has been removed down to dpc. Clearly the screed is going to go from being bonded to the concrete slab transitioning to a strip approx 300m wide where it will be sitting on the dpm from under the slab + the old dpc from the original wall. I can't imagine it will bond to this. Should this be reinforced with chicken wire or similar? Or will the fibres that I'm adding be sufficient?
3. Similar to above. At the back of the old garage wall, the bonded screed of the extension will transition over the old single skin dpc of the rear garage wall into a floating screed over the celotex. Should this area be reinforced or will the fibres be enough?
4. I'm also a bit green when it comes to mixing the screed. I have the use of an electric mixer which sits on the floor. I'm unsure of the best process for converting the sand/cement which will be at the front of the house, into screed that is needed in the extension. I'm thinking that it will be impossible to get the mixed screed from the mixer into a wheelbarrow as the mixer is too low, therefore it would be best to have the mixer in situ. How long is it recommended to mix the screed for before it is fully mixed? Is it best to add the ingredients in a particular order?
5. I'm thinking of laying the screed in one big strip with a baton on one side for levels and the existing screed on the other. This will be approx 2.5m wide. Is this feasible or will it be much harder? It avoids the need for a central rail and the hassle that entails. It doesn't need to have a perfectly smooth finish as I'll be tiling over it.
Many thanks for any help that is offered.