Can you fix Balustrade on top of Screed?
Posted on 22nd June 2023Floor build ups typically consist of a portion of screed and so it is important to understand how this will impact the Balustrades in your construction project.
So, is it possible to directly fix Balustrades to floors with Screed?
Firstly, a basic understanding of screed might help: “Screed is a thin layer of material that is placed on top of a concrete subfloor. Usually, screed consists of cement and sharp sand, but where a more industrial version is required, coarse aggregates can be added to create a thicker layer.“
Now the answer to the question of ‘Can you fix Balustrade on top of Screed?’ has two depending factors…
- Whether there is insulation between the screed and concrete
- The depth of the screed itself
To assist in answering this question, we have prepared a schedule that could be referred to as a guide. Click here to download our guide.
Screed / Insulation depth
Balustrades cannot be directly fixed to screed because the screed doesn’t provide any strength and in fact, puts more strain on the fixing. If there is insulation between the screed and the concrete slab then the answer is a definite no – pockets must be left out, or cut out, of the screed so that the baluster (Not sure what a Baluster is? see a full breakdown of Balustrade jargon here) can be fixed directly down to the concrete below.
If there is nothing between the screed and concrete slab then there is a chance that the balustrade post could be fixed on top of the screed with the bolt fixings extending through into the substrate below.
Due to the screed providing no tensile strength to the fixing, the depth has to be considered as a very large spacer or packer between the base of the post and the fixing substrate (concrete). Consequently, screed just works as material clamped in compression.
Taking this into consideration, if the depth of the screed exceeds 70mm, it becomes very difficult to achieve the loadings and pockets must again be left out to enable a direct connection to the concrete.
Other balustrade & screed considerations
Another key consideration is the loading requirements of the balustrade as for higher loadings, it is increasingly unlikely that any fixing through screed is possible at all. Further to this, it’s important to mention that building designers are recommended to consider the location and position of any under floor heating pipes. Where they come close to the stair, it must be ensured that there is no possibility for clashes with baluster posts.
Concluding remarks
To wrap-up, there are many factors to consider, but unless the screed is relatively shallow, it is increasingly difficult to get a sufficient capacity from fixings for the balustrade loading. This is due to the screed having to be considered simply as a packer rather than any form of substrate.
Need something to refer back to? Download our detail guide here.