Hi there - I am familiar with the area of Balbriggan and housing prices.
I can tell you that there is an estate in Balbriggan that was sold with 40% social/affordable housing. This has brought some social problems, exacerbated by investors renting out houses in the estate, this reduced the number of owner / occupiers and residents have had problems with some of the investor's tenants as well as the social housing recipients.
As a rule of thumb, residents have found that difficulties with social/affordable housing residents are much easier solved as the council have been very supportive. Difficulties with tenants of investment properties were not so easy to iron out, and many of the residents are still having problems with anti social behaviour.
However, with regard to housing prices - this estate that I am mentioning has seen quite a rocket in prices since the first phase was built. As a guideline, 4 bed homes in this estate were first marketed 3 years ago in the region of €200K. At present, while there are no 4 bed houses in the estate on the market, they would be valued in the region of €300K - that's an increase of €100K in the space of 3 years.
Mount Rochford is one of the most popular estates in Balbriggan & there is a large demand for 4 beds to let in the town.
I hope this is of some help to you, if I can answer any further queries I will.
Mo