Blockwork sitting on top of I beam. Iv tried filling the void with timbers at every 300-400 covering with building paper/roofing felt and covering again with riblathe. All joints crossed at least 400mm. We have tried filling the void with cement board aswell doing thin coat with mesh and topped with sand+cement but always after a few month's hairline cracks appear at the 2 ends where the I beam sits on the concrete pad and some cracks where the timbers were inserted behind the felt or cement board.
We're starting a job tomorrow and there is an I beam above the front door 4 metres long. I'm sick of the other ways not working so I was thinking of filling the void in the I beam with an external insulation board (void 50mm deep) and cover with double layer of fibre mesh and 6mm basecoat 150mm onto the blockwork and topcoat with sand + cement. I rang an ewi engineer in our local area and he said sand +cement has never been tested over polystyrene insulation boards. He reckons they will swell with heat/moisture. My answer was so does timber and this is the way they advise people to tackle these details. Has anyone ever tried basecoat over insulation followed by sand+cement topcoat.
We're starting a job tomorrow and there is an I beam above the front door 4 metres long. I'm sick of the other ways not working so I was thinking of filling the void in the I beam with an external insulation board (void 50mm deep) and cover with double layer of fibre mesh and 6mm basecoat 150mm onto the blockwork and topcoat with sand + cement. I rang an ewi engineer in our local area and he said sand +cement has never been tested over polystyrene insulation boards. He reckons they will swell with heat/moisture. My answer was so does timber and this is the way they advise people to tackle these details. Has anyone ever tried basecoat over insulation followed by sand+cement topcoat.