Cracked Render

23 Oct 2006
Reaction score
United Kingdom
My mid-terraced house dates back to 1870 and is built from concrete-like blocks whose face is around 1.5ftx1ft (I am a beginner in this sort of thing); described in our survey when we bought the property as "unusual but sound".

We now have a horizontal crack in the render and a small crack reaching down from the same "concrete" window sill on the first floor. Would I use the same render-repair methods outlined above or do I need a specialist? From having read the comments on this subject above, I am assuming that the cracks are due to water getting in from dodgy soffits, holes in the render from a new BT line being run up the front of the house and from render being cut away for the replacement windows.

I'm also assuming (and here I am being really niave) that there is no structural cause, as the horizontal crack carries along across the face of both next-door neighbours, one of whom recently bought the house with a structural survey that said no subsidence.

Any help gratefully recieved.

Sponsored Links
You can and should not rely on a survey to another property as representative of your own property.

A long horizontal crack in render is indicative of movement in the wall behind it, and the crack typically follows a mortar joint. Whether this is significant, recent or historic is another matter.

The areas around the crack should be tapped to see if there are any hollow spots. Its no good just repairing the crack if other ares need renewing too
1870 in Sussex? I wonder what these blocks are? Do they appear to be stone or some kind of brick or concrete material? Are they just used on the outside faces, or on the party walls as well? Or could it be that grooves have been moulded into the render to give the appearance of stone blocks?

Is there a cellar, or is it earth under the ground floor?
Sponsored Links
Is it just 1 horizontal crack?
What height is the crack?
Whereabouts in sussex are you?

Also you say its built from unusual blocks then say its rendered, is the render a recent addition?
Dear all,

Thanks for this advice. It is just one horizontal crack. Yes, it is possible that the walls are a concrete-like material and shaped to look like blocks.

The material is inside and out and party walls (almost impossible to drill into as well) The horizontal crack is about level with the floor of the first floor. I'm near Horsham and it looks like the render has been replaced a number of times over the years - I have no idea when this coat was applied. There is no cellar - just earth under a gap under the floor of about 4 or 5 inches.

I've tapped the area and as far as I can tell it appears to just be the render lifting away from the wall - is this possible and could be it be caused by water getting in, especially from the replacement window frames?

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local