Hi everyone - this is my first post - so hope I've not made any school boy errors!
Background:-
After saving up for a few years I had my garden redesigned & selected what seemed to be a good contractor to undertake the works. The job involved levelling my rear sloping garden & creating a nice big (7m x 11m) patio, and new level lawn terrace around 15m x 11m. There are a few walls built, 1 fairly large 1.2m High retaining wall & steps up to the new lawn from the patio. See pics.
I agreed a fixed price agreement with the contractor who struggled to complete the work in the time they expected because of bad weather during March & April of this year. As a result I believe they rushed some of the work & cut corners which has left a few problems. They are no longer returning any calls despite providing a 10 year guarantee, so I find myself having paid out, but needing to remedy some of the work per below.
The issues I need help with from the site works area of the forum:-
Issue 1:
In a lot of areas along the base of one of the new walls the render is bubbling up. Upon pushing the bubbled areas it's easy to pick the concrete render off & dig out soft sandy / red colour paste from behind. It's very soft & damp (not powdery).
I took a lot of pictures when the work was being done & upon looking closely today I think I've found the problem. There is a metal beading strip along the base of the wall which has been 'stuck' in place with what looks like bonding plaster to tack it up, before the render scratch coat was applied. The areas which are soft seem to be where that 'bonding' type material was applied.
I have no idea what they made this 'bonding' coloured stuff from - so have a couple of questions
- Does anyone know what this stuff is & is it usual to do using this method?
- To repair it my plan is to cut & rake off all the render, bonding, and scratch coat back to the red brickwork, then repair. From my pics of when the work was being complete, that looks like about 2 courses of bricks up from the base of the wall.
What is the best way to repair so that when it's finished & painted it looks as seamless as possible? do I need to apply a scratch coat, then a top coat? If so is this a DIY job, or to get a good top finish would I be best to get a builder to do the work? I have not done any rendering or plastering etc. but am fairly happy to try most DIY...
Issue 2:
Along the top of the wall the edging strips have not been set firmly in place when they were rendered in place. The wall has got a lot of hair line & growing cracks, especially where people have sat on the edge. When you push the corners of the wall then edging strips are springy under the render which is cracking. I presume the only way to fix this is to break all the render off & reseat the edging strips, then re-render?
I'm going to try to create links to the pictures now - please give me some time if they are not available yet...
Thanks for any help in advance.
All walls, steps, patio, and middle lawn are new.
The render is soft to touch where its bubbling & is only soft where the bonding type mix is holding the metal edging in place.
see the 'red-ish' colour bonding type material tacking the metal strip in place along the base of the wall - that's what I think has gone soft, or was never allowed to dry before render was applied.
Issue 2: this shows the cracking corners which run along the top of all of the rendered walls.
Thanks for the reply Dylan - I have also thought it maybe frost damage - it was frosty around the time the rendering was done on a couple of days. One thing that leads me to think it maybe that 'bonding' mix is because there is no other soft areas along any of the walls where the bonding was not used. (left & right walls, also the left side of the wall where the current damage is presenting).
The edging strips need to be a full bed, not dot and dabbed. A scratch coat will be needed. Use sbr not pva as pva is no good in damp areas. Hack off all the lose render around the failed render. The top coat needs to be stronger than the scratch coat.
Hi Giles, The wall was tanked from the rear all around the lower walls were tanked using a black tanking paint & the tall wall with a very thick plastic sheet (like a subfloor DPC type material). You're right that there are no weep holes - if I do get damp coming through then I may dig out the beds & fit properly. It's worth noting that this bubbling started about 6 weeks after the building & filling of the beds - so given the wall is a double skin of red brick & concrete block (with wall ties & an air gap) I'd would not expect it soaked through that quickly.
The balustrades have been ordered (from www.stainlesshandrailsystems.co.uk) and are going to be installed along the entire width of the tall wall & run around & down the stairs with steel wiring / steel handrails. I have not fitted them yet because I'm still trying to get the contractor who did the ground work to come and fix their poor work - I'm guessing the minute I drill the render to fit the fence posts then if he ever does come back it'll be blamed on my drilling
Regarding the sloped areas - they are going to be meadow seeded in the new year - money ran low, so I decided to invest in the ground work & fence / balustrades for now!
Hi Sean - thank you for the guidance. So, after I hack off all the lose render, what do I need to do with the edge strips - leave them in place & trowel new scratch coat over them, or remove them and reseat them in a thin later of concrete, then once that's dry, put on a scratch coat, let that dry then mix SBR in to the top coat & apply?
why would you not expect it to soak through so quickly?
if there is no where for the water to go the hydraulic pressure will burst it through and it'll either drop into the cavity and give you a wet lower section to your outer skin or track across the wall ties
the big wall looks like block laid flat and the steps wall looks to be just a single skin?
Giles
Groundworks and Equestrian specialists, prestige new builds and sports pitches. High Peak, Cheshire, South Yorkshire area.
trickysummer wrote:Hi Sean - thank you for the guidance. So, after I hack off all the lose render, what do I need to do with the edge strips - leave them in place & trowel new scratch coat over them, or remove them and reseat them in a thin later of concrete, then once that's dry, put on a scratch coat, let that dry then mix SBR in to the top coat & apply?
If it is sound and level on the edge strips just fill in with render, not concrete. By the way are they the outdoor type edge strips, not liable to rust? Paint sbr on the patches to help the scratch coat stick. Covet you flags to stop staining.
The bonding material looks like it might be exactly that, thistle bonding. Its totally unsuitable for outdoor work and will soak up water like a sponge.
The beads should be plastic as said above and are possible just normal indoor beads which would tie in with the use of bonding. The plasterer probably had them in the van and didn't bother to get the right ones...
Hack off and replace the stop bead and perhaps uncovr a bit of the corner beads where its cracking. You may need to use copings, rendered wall tops just don't last.
its pure idleness on the plasterers part
all he had to do was tack the beads on with galvanised nails,I have seen this exact same problem on a refurb recently and the plasterers had used bonding to fill holes and stick the beads.I had to go back and lay suitable copings with lots of SBR as the lot went like this
LLL
