Tieing into soil/waste pipe?

ste15

Hello, I am building a workshop in my garden, I will need a sink for work, I thought I may as well install a toilet in there aswell as I am going to have to tie into the waste pipe somewhere. The waste pipe runs straight out away from the back of my house and about half way up the garden it drops into the main sewer pipe. My workshop is at the end of the garden facing the house. Do I have to run a waste pipe from my workshop up to the small manhole at my house, or can I tie into the waste pipe adding a seperate small manhole, or do I tie in directly to the main sewer pipe? Also, how do I calculate the fall on my new waste pipe, because the garden falls towards the workshop, so I need to make sure that its even possible to get enough fall on the new soil pipe? Any advice is always useful please. Thankyou.

items

If your connect to a main sewer then tap into waste pipe where ever you can. Plenty of connecting fittings available, if you have a 4" pipe close by you could connect waste into 4" by using a strapped boss, all you have to do is hole saw through 4" the dia of boss. No real need for man holes either, if your worried about blockages any time you use a 90 bend, fit a tee instead with a mini rod eye.

Their is recommended falls but all depends on distance of travel so I couldn't give figures unless I could psychically measure out travel.

Common sense really, connect waste at the closest location, have enough of a fall, just off level, don't have to great a fall, if to much fall water will go ahead of debris leading to build ups.

I missed the toilet part, your going to have to do some digging, where ever your branching off sewer fit an AJ (access junction) and if you have a few bends again fit another AJ or two. Once you bring 4" to garage you can tap in waste pipe 1" 1/2 or 1" 1/4 as described in first paragraphs.

mossie110

sewer pipe should drop 1/4'' every foot.

ste15

Nice one for the advice, I tied into the surface water drain with a strapped boss already because my workshop would be under 3 inch's of water every time it rained! So I think thats how I will do the soil pipe too seeing as I have done it before. Cheers for leading me in the right direction.:)

items

mossie110 wrote: »

sewer pipe should drop 1/4'' every foot.

Dunno about recommending a measurement like that without knowing the distance, could end up below sewer, it happens.


Sewer fall 1 in 40 to 1 in 110.

Anywhere in between the two is fine. The 1 is each section ie, garage to first AJ 1 in 80 then another 1 in 80 from AJ to next AJ, then another 1 in 80 from AJ to sewer connection AJ.

offalyman

was always told a sewer pipe should drop an inch in 20 feet? If it is anymore the water would run a head of the waste, leaving the waste in the pipe and if it was less the water wouldn't run fast enough to carry the waste.

i think to need to have a look at your levels and see for yourself where the heights work out best for you. there is always the option of letting the waste run to a sump and pump it to the man hole if you run into height trouble. these pumps are 10 a penny and cheap to run with the float switches available on them now

ste15

I think I'll go with what items said, a bit of common sense, I will measure up how far I will need to travel the soil pipe and then try and get the depth of the 4'' waste coming away from the house by digging down. If its not workable I guess I'll be ferrying buckets of waste water up and down the garden! I will also have to have a stack on the workshop too wont I, for venting gasses?

items

ste15 wrote: »

I think I'll go with what items said, a bit of common sense, I will measure up how far I will need to travel the soil pipe and then try and get the depth of the 4'' waste coming away from the house by digging down. If its not workable I guess I'll be ferrying buckets of waste water up and down the garden! I will also have to have a stack on the workshop too wont I, for venting gasses?

Just edited post above with sewer formula.

A lot of people make mistake by thing a sewer vent is to vent out gasses etc, the vent is more associated with opening waste pipe work to atmospheric pressure (gravity). Without gravity toilets wont flush, basins wont empty. If you have an existing vent close by you could fit toilet without adding another vent, just depends how close. Its not a big job either way, come up with new sewer directly behind toilet (outside wall) @ 7 1/2 " from finished garage floor place a tee to pick up toilet then carry on up with vent 1m away from openings.

ste15

Never knew that about the gravity pressure, I think I will put in a stack, sure its not much extra work anyway. Thankyou for all the information, definitely more sure of what I'm doing know.

items

ste15 wrote: »

Never knew that about the gravity pressure, I think I will put in a stack, sure its not much extra work anyway. Thankyou for all the information, definitely more sure of what I'm doing know.

http://www.arca53.dsl.pipex.com/index_files/drain7.htm

Check out that site, everything you need to know to work out fall there.