Help & Advice
To achieve good compaction of the concrete during the pour it is advisable to have a concrete vibrating poker available on site. The vibrator should be of a reasonable size between 25 mm and 32 mm diameter. Larger pokers designed for mass concrete pours and slab foundation work should not be used. If only the larger poker is available on site then it can be placed against the reinforcement to vibrate down into the wall.
The Polarwall formwork can also be vibrated adequately from the outside of the formwork. This is usually done with a piece of timber held against the polystyrene and firmly hit with a lump hammer or mallet. Another method is to use an SDS drill with an attachment to be held against the form work whilst the drill is set to impact mode.
The critical elements to vibrate are reinforced walls such as retaining walls, and when building above ground the sides of the windows and openings, as well as the lintel areas are critical.
it is good practise to try and keep the lintel area free of concrete snots during the pour so keep them covered when filling the wall up. Then fill the lintel area in one pass.
Over-vibration of the concrete can create problems within the structure,, as excessive vibration will drive the aggregate to the bottom of the formwork resulting in a poor mix. Also over-vibration especially with an internal poker vibrator can cause an increase in pressure so a sensible approach must be taken.