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Patio horror
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Do you have any way to access the soakaway should it block?TELLIT01 said:We have had the roof of our large conservatory draining into a soakaway for nearly 15 years and never had a problem with the drain blocking due to debris from the roof. It certainly shouldn't happen within a very short time of installation. Add to that the downpipe terminating above the drain grating, any rubbish would build up on top, not in the drain.0 -
cmonwigan said:
Do you have any way to access the soakaway should it block?TELLIT01 said:We have had the roof of our large conservatory draining into a soakaway for nearly 15 years and never had a problem with the drain blocking due to debris from the roof. It certainly shouldn't happen within a very short time of installation. Add to that the downpipe terminating above the drain grating, any rubbish would build up on top, not in the drain.
No. I'm not even sure where it is! I don't see any reason a soakaway should block as it's only basically a pile of rubble. I should have mentioned, there is a grille over the top of the downpipe, but even that hasn't ever blocked up.
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Pointing mix looks very weak. Had a patio laid a few years ago where the contractor was almost phobic about using cement. Pointing quickly washed out and had to be redone.2
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Did the builder install the soakaway or was it pre-existing? If the latter, how old is it (they have a 20yr life expectancy).Why was the patio not sloped away from the house? (= might have been job creation advice)The pointing is of cowboy standard and needs to be redone. The builder redid it on my back patio but it crumbled again within 6 months = the weeds are happy!You could ask the Furniture & Home Improvement Ombudsman for mediation help.FYI I have an aco channel on my land which is cleared of leaves in Autumn and again for other detritus in Spring (by my home help but an easy job if able bodied).1
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It's a new soakaway installation. Possibly the depth and or the number of crates was not sufficient and hence the poor performance. The ground is clay, but he assured me that his perforation test was fine.Jellynailer said:Did the builder install the soakaway or was it pre-existing? If the latter, how old is it (they have a 20yr life expectancy).Why was the patio not sloped away from the house? (= might have been job creation advice)The pointing is of cowboy standard and needs to be redone. The builder redid it on my back patio but it crumbled again within 6 months = the weeds are happy!You could ask the Furniture & Home Improvement Ombudsman for mediation help.FYI I have an aco channel on my land which is cleared of leaves in Autumn and again for other detritus in Spring (by my home help but an easy job if able bodied).
However every time it rains there is yet more mortar material run off, so I think this is going to or has already blocked the pipe.
With regard to the slope, we wanted a curve to the patio and I was advised that the aco drain would therefore have to be next to the house. I think they had planned to feed into the main drain, but as explained there's no access to one from the garden. The original patio was just shingle, with a buried perforated pipe connected to the drain going away from the house.
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Just going off your user name- this guy wasn't called john was he?1
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I ran a query into Ghatgpt, basically to calculate the recommended size of soakaway. I was asked to enter the roof and patio in sq metres. The area of roof to be used by the arco/soakaway is 80m2 and the patio is 60m2.
Chatgpt recommended a soakaway capacity of 1.82 cubic metres (m³). We currently have 1 cubic metre. I will send this info onto the landscaper and ask for comment. We had more heavy rain this morning, the pipe is again backed up and the drainage channel has an inch of sitting water still. Below is how Chatgpt came up the sizing...Using a general rainfall intensity of 10 mm/hr and a standard soil permeability. We’ll also assume the runoff coefficient is 1.0 for both the roof and the patio, which means that all the water that falls on these surfaces will be considered for runoff.Calculation Steps- Convert Rainfall Intensity:
- 10 mm/hr = 0.01 meters per hour (m/hr)
Calculate Runoff Volume per Hour:- For Roof: Runoff Volume=Roof Area×Rainfall Intensity\text{Runoff Volume} = \text{Roof Area} \times \text{Rainfall Intensity}Runoff Volume=Roof Area×Rainfall Intensity Runoff Volume=80 m2×0.01 m/hr=0.8 m3/hr\text{Runoff Volume} = 80 \, \text{m}^2 \times 0.01 \, \text{m/hr} = 0.8 \, \text{m}^3/\text{hr}Runoff Volume=80m2×0.01m/hr=0.8m3/hr
- For Patio: Runoff Volume=Patio Area×Rainfall Intensity\text{Runoff Volume} = \text{Patio Area} \times \text{Rainfall Intensity}Runoff Volume=Patio Area×Rainfall Intensity Runoff Volume=60 m2×0.01 m/hr=0.6 m3/hr\text{Runoff Volume} = 60 \, \text{m}^2 \times 0.01 \, \text{m/hr} = 0.6 \, \text{m}^3/\text{hr}Runoff Volume=60m2×0.01m/hr=0.6m3/hr
- Total Runoff Volume per Hour: Total Runoff Volume=0.8 m3/hr+0.6 m3/hr=1.4 m3/hr\text{Total Runoff Volume} = 0.8 \, \text{m}^3/\text{hr} + 0.6 \, \text{m}^3/\text{hr} = 1.4 \, \text{m}^3/\text{hr}Total Runoff Volume=0.8m3/hr+0.6m3/hr=1.4m3/hr
Determine Soakaway Size:Soakaway Volume=Total Runoff Volume×1.10\text{Soakaway Volume} = \text{Total Runoff Volume} \times 1.10Soakaway Volume=Total Runoff Volume×1.10 Soakaway Volume=1.4 m3/hr×1.10≈1.54 m3\text{Soakaway Volume} = 1.4 \, \text{m}^3/\text{hr} \times 1.10 \approx 1.54 \, \text{m}^3Soakaway Volume=1.4m3/hr×1.10≈1.54m3- A common rule of thumb is to size the soakaway to handle the runoff from a specific duration, such as a 1-hour rainfall event. In this case, we are assuming a basic design requirement where the soakaway should accommodate at least the total volume of runoff expected in an hour.
- To account for soil permeability and ensure adequate drainage, a common guideline is to size the soakaway to be at least 10% larger than the total runoff volume to allow for settling and to handle variations in soil absorption.
SummaryFor your roof and patio areas, you should aim for a soakaway with a minimum capacity of approximately 1.54 cubic meters (m³).With clay soil, the infiltration rate is lower compared to more porous soils like sand. This means that water will drain more slowly, and you might need a larger soakaway to handle the runoff effectively.
Here’s a revised approach taking clay soil into account:
Soil Considerations
- Clay Soil: Typically has a lower infiltration rate, often around 1-3 mm/hr, which is quite slow compared to sand or loam.
Revised Soakaway Design
Calculate the Volume of Soakaway Based on Infiltration Rate
Given the slow infiltration rate, you might need a larger soakaway.
For clay soil, a common recommendation is to size the soakaway to handle not just the runoff volume but also to account for slower absorption. A typical recommendation is to provide a soakaway volume of around 20-30% of the total runoff volume to ensure that the water is adequately managed.
Revised Soakaway Volume Calculation
Total Runoff Volume: As calculated before, is 1.4 m³ per hour.
Soakaway Size Adjustment for Clay Soil: Soakaway Volume=Total Runoff Volume×1.30\text{Soakaway Volume} = \text{Total Runoff Volume} \times 1.30Soakaway Volume=Total Runoff Volume×1.30 Soakaway Volume=1.4 m3×1.30≈1.82 m3\text{Soakaway Volume} = 1.4 \, \text{m}^3 \times 1.30 \approx 1.82 \, \text{m}^3Soakaway Volume=1.4m3×1.30≈1.82m3
The 30% increase accounts for the slower infiltration rate of clay soil, ensuring the soakaway can handle the water effectively.
Summary
For clay soil, you should design your soakaway to have a minimum capacity of approximately 1.82 cubic meters (m³). This extra capacity helps accommodate the slower drainage and potential accumulation of water.
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Wow - that is so impressive. Along with the crumbling pointing, I would think that the job is not fit for purpose but no doubt the MSE experts can advise you.I note you wanted a curved patio but sloping this away from your home should not be beyond the competence of a good builder = he just needed to slope the land and lay a curve on it instead of a straight line.1
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