What is screed and what does it do?
Screed is one of a number of specialist concrete mixes, which is then applied – often by pouring – onto an existing concrete base. The purpose is to create a perfectly level, smooth and even floor, ready for covering or polishing.
Why do I need screed if I have a level concrete base?
You might not if the concrete base is outside and you don’t need a smooth finish. But concrete uses a larger, coarser aggregate mix and seldom offers the smooth finish required to take other flooring finishes. Even laying paving slabs over a screed can be easier and offer better results than laying directly on a concrete mix.
How long does screed take to dry?
This can vary significantly according to the type of screed used. The earlier you involve a specialist screeding contractor in the design process, the more control you have over defining your timetable and the best screed to meet that and the end-use requirements. Some screeds with specialist additives can be ready to walk on in as little as 12 hours. Others may take up to 48 hours before they can take foot traffic. The time between curing and applying further finishes or even furniture varies too, but will typically be between two and four weeks. We can perform a screed test to ensure the floor is ready to take surfacing such as carpet or tiles. There are also some fast-setting screeds which can be used to accelerate a project timetable, particularly with refurbishments and fit-out, but it’s always recommended to consult a screeding expert to aid in scheduling.
Does the floor need to be prepared before applying a screed?
Usually, yes. Among other things, we use specialist equipment to strip away any remnants of existing adhesive and loose debris, to ensure that the substrate is in the best condition for bonding with the screed. There are various techniques available, depending on what’s needed: repairing any cracks or joints in the sub-surface or filling in any significant holes; diamond grinding; scarifying; and shot blasting. Good preparation is essential to a long-lasting surface. If a DPM membrane is required, the preparation requirements are significantly reduced, however.
What are the maintenance requirements for screed?
If it’s been applied properly, and it’s the right screed for the environment, none whatsoever!
How thick should screed be?
This varies according to the type of screed being poured and the purpose and location of the floor itself. A residential screed would not need to be as thick as the floor of an industrial warehouse, for instance. Thin-section screeds, on the other hand, are often self-levelling and used to level floors which contain minor dips and depressions in preparation for taking a resin coating or floor paint. Other factors in screed depth include whether the floor requires any pre-screed insulation or underfloor heating. Perhaps the shallowest depth of screed is a bonded screed in a light traffic area, which would require a 25mm minimum depth.
So, you can screed over underfloor heating?
With the right screed and the right preparation, yes. Depending on project needs, you may need or want damp-proofing membranes, acoustic and thermal insulation and underfloor heating, all of which can be installed, but each of which require careful consideration for depths and screed types.
Does the weather affect screeding schedules?
Does the weather affect screeding schedules?
Usually not. The important thing is that the ambient outdoor temperature is above 3°C. It does need to retain its moisture though, so if exposed to direct sunlight and/or high temperatures, we need to take precautions to make sure the screed doesn’t dry out before it has cured.
What’s the difference between resin-bonded and resin-bound?
More than you might think. Resin-bonded is loose gravel with a resin layer. It gives a textured surface, it’s non-porous and can break up over time. Resin-bound involves a manufacturing process whereby each grain of aggregate is coated in resin; it results in a totally smooth finish which can also be porous to allow for drainage.
How long does a resin floor take to dry?
The curing time for resin coatings and resin-bound surfaces depends on the product and the temperature. Some epoxy flooring is ready to take foot traffic in a similar time to screed: 24-48 hours. Some fast-curing products are available which can speed up the time from pour to cure. Some resin flooring can be ready for a building’s users to return to work in as little as two hours!
Does the temperature affect curing times for resin floors?
It’s more that some resin systems are designed differently. So, some epoxy and polyurethane resin coatings need temperatures above 15°C – they need warmth – whereas others are designed to be cold setting, capable of curing in only a couple of hours at -30°C. Not a temperature we have to work in too often, thankfully!
Does resin coating flooring require a concrete base?
In theory, resin can also be installed on asphalt, tiles or even wood, but a concrete or cementitious base offers fewer challenges. If in doubt, consult an expert with the specifics of the base you’d like to consider resin coating for.
What special properties can resin coating have?
Quite a few, depending on the purpose and site of application. Anti-slip flooring is a regular request, and other special properties include self-smoothing, moisture-tolerant, chemical-resistant, anti-static, and heat-resistant. They can also be available in a range of colours and decorative finishes. We can advise you on the specifics and the best product for your environment and end use.
Have you got a question about screeding or resin floor surfaces? Get in touch with our team for friendly and reassuring advice you can count on. Call us on 01582 662397 or email [email protected] today.