I want to fit ikea integrated washing machine & integrated dish washer units on a wall with a combi boiler on it. There are numerous pipes going into the bottom of the boiler so we cant have the units flush against the wall. There are limited options to move the pipes or boiler. Therefore I would like to install the units around 10 cm proud of the wall. I am getting a company to install the worktop which will have to be an extra 10 cm deep, & that isn't a problem. I was thinking of just fittitng a piece of timber against the wall at the same height of the units for the worktop to rest on. Was just wondering if the units will be solid enough if they aren't attached to the wall. Is the weight of the worktop enough to keep everything solid? Or should I build some kind of timber frame for the units to back onto?