The Brew Cabin

Posted: **Mon Apr 04, 2005 3:42 pm**

Hi,

I've just located my Foul Drainage Inspection Chamber Manhole Cover which was burried under some concrete slabs forming a patio area at the front of my house. I cleared the blockage but have noted the following:

1. The 'Benching' seems to have come away a little on one side where it meets the edging ridge of the 'Channel' - As a DIY'er is it OK for me to attempt to repair this myself, the chamber is about 4 feet deep although only just big enough to get into? If so, what type of concrete or mortar should I use? Do I need to let the area dry out first and how long should I keep it dry afterwards? Or, can I just leave it as is? Any tips?

2. The frame that holds the manhole cover in place has come lose, what type of concrete/mortar mix should I use to re-bed it on? Any tips?

3. Is it legal for a manhold cover to be 'buried' beneath paving slabs, or should it be accessible at all time. The slabs were not concreted down, simply laid on top!

Cheers

Kevin

Posted: **Thu Apr 07, 2005 9:08 pm**

1 - you can attempt a repair, but it's possibly better left to the professionals because you'll need some special kit and there's a real risk of being overcome by sewer gases. I appreciate this is a minor risk in what is a relatively shallow chamber, but it's real, nonetheless.

So, if you want to do a DIY repair, you MUST have a 'buddy' watching over you while you work in the chamber - any sign of wooziness, nausea, headache, then you get out and stay out. You need to stopper the inflow pipe and use a fast setting mortar. If you can't get 'grano' locally, then use grit sand mixed with sulphate-resisting cement at 3:1 and add Ronafix or SBR to the gauging water to accelerate the setting and improve the bonding. Use a small pointing trowel to patch repair the gap, then thoroughly clean off the tools. A couple of hours later, the reapir should be sufficiently 'hard' and capable of withstanding the flow in the channel once again, so the stopper can be removed.

2 - much easier. Just use a Class II mortar (4:1) There's ohotos of this sort of thing being done on one of the Fitting a RecessTray pages.

3 - Legal/illegal are terms that are a bit too strong. It's a "breach of good practice" and would not be allowed to take place on a new build, but there's no way of legislating for what folk do on their own patios and driveways. You're right in that the access covers should be accessible at all times, but we live in an imperfect world, I'm afraid.

The Brew Cabin

Ic benching & re-securing manhole cover frame